We see lightning before we hear the thunder because sound tr

A. of

B. around

C. off

D. ahead

Sunday was going to be the birthday for me and my other two classmates． As we were born in the (21) month，we decided to have a big party to (22) it．

On that evening，we invited all of our classmates． We prepared a lot of food and drinks．After singing the birthday song，we (23) the delicious cake together． We sang more songs and played games． Then someone told funny stories，and (24) laughed． Three hours flew by quickly．Because we had to (25) before 11:00，we ended our party at 10:00． Before we left，our classmates gave' (26 )0f us a birthday card with their best wishes． ( 27) we took some pictures together． What a great time we had! At that moment，l felt love，happiness and friend- ship．

Before the party，only my (28) could remember my birthday，and l had never had such a big party and so many friends wishes．(29) I wanted to say to my classmates，"Thank you，and I will (30) forget this evening，especially each of you!

( )21．

A．different

B．best

C．same

D．some

A、surrendered

B、thunder-struck

C、impenetrable

D、genetic

A.benefits

B.affects

C.affects

D.effects

A.profit

B.suspend

C.escape

D.route

29． When it thunders, we always see the light before we hear the sound．______ It’s because

A． our eyes are in front of our ears

B． our eyes are cleverer than our ears

C． our eyes can see but our ears can-t

D．light goes faster than sound

Passage Two

When we see well, we do not think about our eyes very often. It is only when we cannot see perfectly that we realize how important our eyes are.

People who are nearsighted can only see things that are very close to their eyes. Everything else is not so clear. Many people who do a lot of close work, such as writing, reading and sewing, become near sighted. Then they have to wear glasses in order to see distant (远处的) things clearly'.

People who are nearsighted suffer from just the opposite problem. They can see things that are far away, but they have difficulty in reading a book unless they hold it at arm's length. If they want to do much reading, they must get glasses, too.

Other people do not see clearly because their eyes are not exactly the right shape. They have what is called astigmatism (散光). This, too, can be corrected by glasses. Some people's eyes become cloudy because of cataracts (白内障). Long ago these people often became blind. Now, however, it is possible to operate on the cataracts and remove them.

Having two good eyes is important for judging distances. Each eye sees things from a slightly different angle (角度). To prove this to yourself, look at an object out of one eye; then look at the same object out

of the other eye. You will find the object's relation to the background (背景) and other things around it has changed. The difference between these two different eye views helps us to judge how far away an object is. People who have only one eye cannot judge distance as people with two eyes.

40. We should take good care of our eyes ______.

A. only when we cannot see perfectly

B. only when we can see well

C. even if we can see well

D. only when we realize how important our eyes are

A.we’ve ever given before.

B.but I got nothing out of it.

C.and there are two hundred and sixteen thousand employees worldwide.

D.I am afraid we can go no further.

We should see the events in their historical ________ before we draw any conclusion.

A respective

B retrospective

C prospective

D perspective

A.in an instant

B.on the instant

C.for an instant

D.the instant