Your concentration levels will most likely______

A.focus

B.concentration

C.care

D.attention

A.statistics

B.atmosphere

C.concentration

D.supplement

A certain reaction, A+B → C, is first order with respect to each reactant, with k = 5.0 × 10^-3M^-1s^-1. Calculate the concentration of A remaining after 100 s if the initial concentration of A was 0. 100 M and that of B was 6.00 M. State any approximation made in obtaining your result.

ers produces your desire to remember and makes your concentration much easier.

A．Y

B．N

C．NG

A．Play cards with your friends.

B．Try to name by means of intense concentration an object placed in the next room.

C．Guess who the caller is before picking up the receiver.

D．Think about a friend you haven't seen or heard for a long time.

using the method of standard additions. When a 50.0-ml sample is analyzed, the peak current is 0.886μA. A 5.00-μl spike of 10.0μg/ml Cu²⁺is adoied, giving apeak current of 2.52μA. Calculate concentration of copper in the sample 0f sea water.

A.3．5mmol / L

B.4．5mmol / L

C.5mmol / L

D.5．5mmol / L

E.6mmol / L

As you may know, the best way to keep. yourself physically fit is to exercise everyday. The __21 __is that you should__ 22 __physical fitness part of your __23__ routine. It is the same with mental fitness.__24_ you want to be able to think well and to learn well, you __25__ exercise your mind daily. As with physical fitness," there are a __26__ of activities you can do to keep incontrol. However, over the__ 27__ run. the very best way to exercise your mind is to _28_the habit of reading. Here is why. Think of the difference between watching television and _29 __a book. Watching television is a passive experience. You sit, you look, and you listen. Such concentration is __30__ by outside stimulation(刺激). Reading a book, on the other hand, requires __31__ concentration.As you read. You must put in agreat deal of effort to look at the words.__ 32__out what they mean, and build up images,thoughts and opinions within your__ 33_ , During your reading. , if you atop concentrating,even __34__ a second,everything stops. Nothing happens until you start concentrating again. For this reason, reading regularly forces you to __35__ your powers of concentration, a skill whose value would be difficult to overpraise.

A.thing

B.problem

C.trouble

D.matter

A.cause

B.make

C.bring

D.turn

A.daily

B.weekly

C.monthly

D.quarterly

A.Until

B.Unless

C.When

D.if

A.may

B.must

C.could

D.would

A.pair

B.set

C.few

D.number

A.long

B.short

C.quick

D.slow

A.change

B.break

C.support

D.form

A.reading

B.writing

C.editing

D.Translating

A.done

B.divided

C.driven

D.drawn

A.passive

B.active

C.low

D.final

A.figure

B.take

C.set

D.look

A.understanding

B.reach

C.field

D.mind

A.for

B.at

C.by

D.in

A.share

B.seize

C.decrease

D.increase

听力原文：W: I got a bad start in the last race. It was hard to eat& up with others.

M: We'll work on your start. The most important thing is concentration before a race starts.

What is the probable relationship between these two people？

A．Daughter and father.

B．Client and lawyer.

C．Athlete and coach.

D．Patient and doctor.

听力原文：Woman: All right, now. Before you step up to the tee, take one practice swing.

Man: I know. And keep my eye on the ball. I remember everything you've told me.

Woman: Good. And don't throw your club. That won't help matters at all. If you miss the ball, just stay calm and try again. You don't want to lose your concentration, so it's really important to stay calm.

Man: All right, all right. I get it. Will you be quiet now so I can try hitting the ball？

Where are the speakers？

A．At a tea party.

B．At a night club.

C．At a golf course.

D．At a bowling alley.