How do you use the simple present, simple progressive, and simple past tenses?

The tenses of verbs are the forms that indicate the time of action or existence.

• THE SIMPLE PRESENT TENSE

This tense has three uses. (1)The present tense can indicate an action that happens or a condition that exists now (in present time), (2) or an action that occurs on a regular basis. (3) It can also be used to express a general truth.

Here are examples of each of these three uses of the present tense:

1. I wonder why that student continues to sit there even though the class is over. [an action happening now]


2. The bus arrives at 7:30 a.m. each morning. [a repeated action]


3. Gold is always valuable. [expression of a general truth]

There is also another use of the present tense, which is called the historical present tense. It is sometimes used in historical writing in order to express past events and more frequently in poetry, fiction, and writing about literature. In journalism, especially in sports writing, the present is used to convey a sense of being there for the reader.

• THE PROGRESSIVE FORM

(There is no simple progressive)
Each of the six tenses has a progressive form that is used to express continuing action [action "in progress"].
To create the progressive forms, one must use the appropriate tense of the verb to be with the present participle of the verb. So, the time of the action is indicated with the auxiliary, or helping verb. 

In order to form the other progressive tenses, the helping verb to be is changed to the appropriate tense, but the participle remains the same.

Here are examples of the six tenses in the progressive form:

PRESENT Mary is sitting in the library. Peter and Joe are sitting in the gym.
PAST       Mary was sitting
FUTURE   Mary will be sitting

PRESENT PERFECT  Mary has been sitting. The girls have been sitting.
PAST PERFECT        Mary had been sitting.
FUTURE PERFECT    Mary will have been sitting.

• THE SIMPLE PAST

The simple past is formed with the past form of the verb. This past tense is used in order to express an action or condition that was begun and completed in the past.
The regular verbs form their past by adding -ed to the present form. Irregular verbs have a separate word, and the verb to be changes to was in the singular and were in the plural form.

Here are examples of the simple past (there is only one verb used):

The baby wanted his pacifier.
The meeting went well. 
The swimmers all won medals. 

Note: The verb to be has two forms in its simple past: was [singular] and were [plural]. For example:

The insurance agent was here yesterday. The repairmen were not here.

A certain full year course has 20 online quizzes spread through the course. The quizzes are optional in the sense that if a student does any of the...

(a) For each question, Tony knows the answer 25% of the time and is forced to guess 75% of the time. His probability of guessing correctly is 20% (1 in 5.)

So the probability that Tony gets a particular question correct on any given quiz is .25(1)+.75(.2)=0.4  (We multiply the probability of having seen the problem by the probability of getting it right; 1/4 of the time he has seen the problem and is guaranteed to get it right and 3/4 of the time he will not have seen the problem and must guess.)

(b) For a given quiz, consisting of 5 questions, we can determine the probability that Tony gets at least 3 questions correct. This is the sum of the probabilities that he gets 3 correct, 4 correct, and 5 correct.

Each of these is a binomial probability, where the probability of a success (getting an answer correct) is 0.4 and the total number of trials is 5:

P(3 correct)=`_5C_3 (.4)^3(.6)^2=.2304 `
P(4 correct)=`_5C_4 (.4)^4(.6)=.0768 `
P(5 correct)=`_5C_5 (.4)^5=.01024 `

So the probability of getting at least 3 correct is
.2304+.0768+.01024=.31744

(c) To find the probability that Tony passes at least 8 of the quizzes we recognize that this is also a binomial probability. The probability of success (passing the quiz) is .31744 and the number of trials is 20. The answer is the sum of P(8)+P(9)+...+P(20).

Computationally easier is to find the complement and subtract from 1: 1-[P(0)+P(1)+...+P(7)]

So we have:

`1-(0.68256^20+20(.31744)(.68256)^19+_20C_2(.31744)^2(.68256)^18+... `

`...+_20C_7(.31744)^7(.68256)^13)~~.2836161405 `

So the probability that Tony passes at least 8 of the quizzes is about 0.2836

(Of course the easiest way to compute this is using technology if allowed. On a TI-83/84 graphing calculator we take 1- binomcdf(20,.31744,7) .)

What is a good material for great traction but low friction?

There's nothing that will provide both high traction and low friction under all circumstances, as the definition of traction incorporates friction and depends on it in order to function. We also can't discuss a single material in terms of its friction or traction properties because both of these depend upon the interaction between two materials, so we'd have to identify a pairing of whatever it is we're trying to move, and whatever it is it's moving on, such as rubber on concrete or iron on iron. 

Friction is the force between two objects that resists their motion perpendicular to each other. Traction is the amount of force that can be generated in the perpendicular direction before the objects overcome their friction force and start to slip. Before this point, friction is determined by "dry friction." After this point, it's determined by kinetic friction.

These are the equations:

Dry friction force (traction) `<=` (coefficient of static friction) x (normal force) 

Kinetic friction force = (coefficient of kinetic friction) x (normal force)

Basically, in the absence of friction, your traction would equal whatever force you applied in the forward direction. Add friction, and suddenly your traction force is reduced. You basically have zero traction until you can overcome the static friction holding you back in the first place. The moment you start moving, you've identified your traction force. After that point, any additional force you spend is used to add to your speed by overcoming the resistance from kinetic friction, since you've already overcome the static friction.

You can't change the normal force (the weight of the moving object), but you can change the coefficients of friction between static and kinetic, depending on the intermolecular and intramolecular forces acting on them.

The only way you might be able to get something that has high traction but low friction is if you're talking about low kinetic friction. Most metal-on-metal pairings will have higher static and lower kinetic friction, as you can visualize with a train struggling to get moving but also struggling to stop due to low kinetic friction. Under these circumstances, we can't really say the train has high traction.

please give a summary of chapter 7 for to sir with love

After having endured the noise of the lunchroom the previous day, Braithwaite decides to eat his lunch in the staff-room. When he sits down, he feels exhausted from the tension of his classroom. As he begins to eat, Miss Blanchard enters and joins him. Soon, they are talking about things that they both enjoy: books, music, theater, and movies. Braithwaite expresses his surprise that the students at the assembly listened to the classical music, and Miss Blanchard agrees.

Then, Miss Blanchard asks him how his day is going. When he tells her, she remarks, "Good Lord. Maybe Weston was right, after all." Braithwaite replies that he has decided to take the advice of Miss Clintridge and maintain order and discipline. When the other teachers enter the room, they also ask Braithwaite how his morning has gone. Weston says that his students do what he tells them, but one of the teacher remarks, "And that's about all you'll get, Big Boy." Soon, comments circulate the room; Weston suggests,"Maybe Braithwaite will try a little black magic on them?" 
"What kind of magic do you try, Weston? Mrs. Drew's voice grew cold. 

Braithwaite leaves the staff-room knowing that almost everyone wants him to do well. As the afternoon session begins, Mr. Braitwaite decides to instruct his class on the measurement system. While he does so, he notices that the students have become surly and watchful.
On the way home, Braithwaite stops into a tobacco shop where he sees rental listings. Once he hears that Braithwaite is a teacher, the shopkeeper tells him that none of the listings are good enough for a teacher, but if he comes back, there may be one for him. Braithwaite is surprised at his remarks.

He smiled and turned back into his shop, and I walked on in wonderment at the amazing unexpectedness of human kindness.

That evening Braithwaite discusses with the Belmonts the situation in the classroom, and all three agree that Braithwaite must gain the students' respect and confidence before their resentment turns into something else.

How is Abigail's attraction to John Proctor evident in The Crucible?

Abigail's attraction to John Proctor can be seen when she admits it and attempts to cling to him in Act 1.  

In Act 1, John and Abigail find themselves alone together. John is definitely uncomfortable with the situation, but Abigail is wonderfully excited to be alone with John again. John attempts to leave, but Abigail rushes to block his path. She then begs for John to say a "soft" word to her.  

He takes a step to go, and she springs into his path.

Abigail: Give me a word, John. A soft word. Her concentrated desire destroys his smile.

Essentially, Abigail is hinting that she wants John to "whisper sweet nothings" to her, as John likely has before. Stronger evidence in support of her attraction to John is in the stage direction about "her concentrated desire." Abigail wants more than mere small talk with John. She is attracted to John, and she's not afraid to remind John of the passionate times they have shared, saying,

I know how you clutched my back behind your house and sweated like a stallion whenever I come near!

Abigail is also not afraid to say she wants those illicit rendezvous again.  

Abigail, grasping his hand before he can release her: John — I am waitin' for you every night.

Why was the police response criticized in the Columbine High School shootings in Colorado? Was the IMS used also criticized?

The killings at Columbine High School on April 20, 1999, seemed to usher in a new era in American life. Since then, we have experienced many shootings in schools, gathering places, and workplaces. While Columbine may always be remembered as the tragedy that started it all, it also taught a lesson to police departments and changed the way they respond to these kinds of horrific events.

Tragically, most of the Columbine killings occurred after the police had arrived and engaged the killers in gunfire. Police training at that time dictated that the officers secure the scene and wait for the arrival of the SWAT team instead of following the killers back into the building and putting an end to their killing. It took the SWAT team 45 minutes to arrive; by then nine more students had been killed, and a teacher bled to death before he was found.

Now, police are trained to make stopping the shooter the priority. Instead of waiting for the experts (the SWAT team), police form their own “contact team” and seek out the shooter, hoping to stop him before he has a chance to kill anyone else.

Regarding the Incident Management System (IMS), Columbine also showed local agencies that they needed to learn to coordinate their responses better. Communication was a particular problem, as agencies used different radios on different frequencies and had not trained together. In such a fluid situation, information must be gathered and disseminated quickly—that didn't happen at Columbine.

In what way are Portia's romanticism and leadership qualities in Act III, Scene 2 contemporary to Jessica's in The Merchant of Venice?

In the first half of the Act III, Scene 2, Bassanio shows up to choose one of the three caskets. The only way to marry Portia is to choose the correct casket between the options of gold, silver, and lead. Bassanio chooses the lead casket, which turns out to be the correct one.

In this first part of the scene, we see Portia's romanticism. It is obvious she and Bassanio are very much in love. Portia even urges him to delay choosing for a month or two so she can enjoy his company in case he chooses incorrectly. Bassanio is in great suspense ("on the rack") until he knows whether he can marry Portia, so he insists on selecting a casket shortly after his arrival. 

In lines 10 -19, Portia is talking to Bassanio, but really thinking out loud, about her dilemma. She could give him a hint about which casket to choose, but then she would be "forsworn" (breaking her word). She refuses to do that, but she fears that, if Bassanio chooses wrong, she will "wish a sin — / That I had been forsworn." She is torn between keeping her word and winning the man she loves.

Jessica is not quite as scrupulous as Portia. She is willing to betray her father, even taking some of his money, so she can run away with Lorenzo. Jessica never explicitly gave her father a promise that she would not run off and marry a Christian. Her "betrayal" is more a betrayal of Shylock's unreasonable expectations of her than it is of any real duty. Shylock is a harsh and repressive father who makes some form of rebellion a necessary part of growing up. Portia's father (who stipulated the casket test in his will) was a loving father who, though his methods might have been strange, had his daughter's best interests at heart. 

Jessica certainly loves Lorenzo, but she expresses herself in a less ardent and more lighthearted way than Portia does toward Bassanio (see Act V, Scene 1).

In the second half of Act III, Scene 2, the tone changes dramatically. Lorenzo, Jessica, and Salerio show up, with a letter from Antonio saying all his ships have been wrecked, he has no way to pay his debts, and he is about to die because Shylock is demanding his pound of flesh. Jessica is able to confirm this.  

Now there is a crisis, and Portia's leadership ability comes to the fore.

Portia notices Bassanio blanch as he reads the letter and realizes something is very wrong. Once she understands the situation, she urges Bassanio to go at once, taking her money worth several times Antonio's debt to Shylock, and gets Bassanio's friend out of trouble. She recognizes the urgency of the situation and will not let him stay even one night after they marry, saying,

First go with me to church and call me wife,

And then away to Venice to your friend. . . 

My maid Nerissa and myself meantime

Will live as maids and widows. Come away!

Of course, the reader knows, though Bassanio does not, that Portia has a contingency plan in mind in case Shylock does not accept money as payment of his debt. Her quick action, in this scene and in later scenes, saves Antonio's life.

Jessica is never put in a position comparable to this one, but she is certainly willing to take quick and decisive action (disguising herself and running away with Lorenzo) to be with her love and get herself out of a bad situation.