【B18】A．afterB．untilC．byD．during

The【B4】of a canal depends on the kind of boats going through it. The canal must be wide enough to permit two of the【B5】boats using it to【B6】each other easily. It must be deep enough to leave about two feet of water【B7】the keel of the largest boat using the canal.

Some canals have sloping sides, while others have sides that are nearly【B8】Canals that are cut through rock can have nearly vertical sides.【B9】, canals with earth banks may【B10】if the angle of their sides is too steep. Some canals are lined with brick, stone, or concrete to keep the water【B11】soaking into the mud. This also permits ships to go at【B12】speeds, since they cannot make the banks fall in by【B13】up the water. In small canals with mud banks, ships and barges(大平底船) must【B14】their speed.

When the canal goes【B15】different levels of water, the ships must be【B16】or lowered from one level to the other. This is generally done by【B17】of locks. If a ship wants to go up to higher water, the lower end of the lock opens to let the boat in. Then this gate closes, and the water is let into the lock chamber from the up- per level. This raised the level of the water in the lock【B18】it is the same as the upper level of water. Now the upper gates can be opened to【B19】the ship into the higher water. Some-times a canal contains a series of locks when the【B20】in levels is very great.

【B1】

A．take

B．save

C．cost

D．waste

B．She will not work on it till tonight.

C．She is very unfortunate.

D．She has got another thing to do.

Corrine Mckillop: I'd like to know which it is. It's very confusing. Is it good or is it not good？

Narrator: Well, a new study may explain the conflicting information. According to the research, coffee can be both good and bad. It all depends on you and which version of a gene you have.

Dr. Sean Kenniff: Researchers believe that about haft of us axe carrying a gene that allows the body to break down caffeine quickly. The rest of us have the type of gene that more slowly metabolizes the stimulant.

Narrator: In the study scientists discovered coffee drinkers with the faster version of the gene had no increased risk of heart disease; however, people with the gene that breaks down caffeine slowly had a significantly higher risk.

Dr. Sean Kenniff: When the caffeine circulates in your body for a long period of time, you might in fact experience adverse health consequences from that. Now all of us want to know the same thing.

Corrine Mckillop: Well. I'd like to find out what gene I have.

Narrator: Well, that's the bad news. There is a test to find out, but it probably won't be readily available for a while. So what to do until then, the answer is, in a word—moderation. The study also found that people with a slower gene can limit their risk if they limit their coffee to one or two cups a day.

(23)

A．The influence of coffee on the heart.

B．What kind of gene is beneficial to people.

C．How to find out what gene one has.

D．How many cups of coffee people should have each day.

B．Coffee drinkers with a faster version of the gene.

C．People who drink coffee three times a day.

D．People who drink alcohol much.

A．Education in the Renaissance

B．Humanism in the Renaissance

C．Debate on Education

D．The New Education

A．discovered after great efforts

B．found out quite by chance

C．amazed and confused by

D．invented in experiments

B．They could greatly improve their work efficiency.

C．Many cancer cases could be prevented.

D．Many embarrassing situations could be avoided.

A．engages

B．intends

C．deliberates

D．signifies

M: Let me see, I need to find a handle that matches, but that shouldn't take too long.

Q: What does the man mean？

(13)

A．There is no replacement for the handle.

B．There is no match for the suitcase.

C．The suitcase can be fixed in time.

D．The suitcase is not worth fixing.

W: That may be so. But in the letter, I just told him frankly I could no longer live with his poor management and stupid decisions.

Q: What do we learn about the woman？

(15)

A．She has made up her mind to resign.

B．She has often been criticized by her boss.

C．She cannot stand her boss's bad temper.

D．She never regrets any decisions she makes.