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A．Students were unwilling to cooperate when he conducted the poll.
B．There was no available data of the racial composition of every school.
C．He found it impossible to catalogue the structural feature of all high schools.
D．It was difficult to compare the racial makeup of the clubs and sports teams.
答案
更多“What problem did Clotfelter face when he studied the effect of schools' extracurricular ac”相关的问题
第1题
What did people do to solve the problem of rain lack around Chad Lake？
A．They moved out of this area.
B．They drew water from Lake Chad.
C．They carried water from other areas.
D．They utilize sea water near this area.
第2题
听力原文：W：How did you like biochemistry？ I've signed up for next semester.
M：It was a breeze. No problem at all.
Q：What does the man think of biochemistry？
(13)
A．It was quite easy.
B．It was too difficult.
C．It was useless.
D．It made one feel dizzy.
第3题
M: Did you hear a crash, that was it, I'm just as clumsy as ever.
Q: What is the problem？
(16)
A．The woman doesn't like jam.
B．The woman forgot where she had left the jar.
C．The man had an accident.
D．The man broke the jar.
第4题
M: I had the same problem until I took up mountain climbing.
Q: What did the man and woman say about heights？
(14)
A．Both of them have overcome their fear.
B．They are both afraid of high places.
C．The woman is still afraid of high places, but the man isn't.
D．Both of them prefer high places these days.
第5题
W：Don't you think that I am trying to figure it out？ But I simply couldn't pin her down．
Q：What can we learn about the conversation？
(18)
A．Rachel has some problem with her husband.
B．It's hard to know Rachel's real feeling.
C．The man has got no chance to talk with Rachel.
D．The woman knows what Rachel is thinking about.
第6题
B: Yes, Professor Smith. We did.
S: Who's your lab partner, Bob？
B: Anne Wilson.
S: Well, Anne, can you and Bob go over the procedure for the class？
A: Sure. Firs(we put ten grams of crushed limestone in a bottle.
S: Anything special about the bottle？
B: It was a gas - collecting bottle with a one - hole stopper and bent glass tubing.
S: Very good. So you put the limestone in a gas - collecting bottle. Then what？
A: Then we poured in ten milligrams of hydrochloric acid, put on the stopper, and collected a bottle of carbon dioxide.
S: Right, What was the method of collection？
A: Water displacement.
S: Good.
A: Then, we lit a magnesium ribbon and put it in the bottle or carbon dioxide.
B: And carbon deposits began to form. on the bottom of the bottle, You see, we didn't have any problem with procedure.
A: Well, we had a little problem getting the magnesium ribbon to stay lit until we could get it into the bottle.
B: Okay. But we did it. The big problem was that we really didn't understand what happened. Did the magnesium combine with the oxygen in the carbon dioxide？
S: You have just answered your own question, Bob. The burning magnesium broke the carbon - oxygen bonds in the carbon dioxide, and then the oxygen combined with the magnesium to produce magnesium oxide.
A: And the carbon was freed to deposit itself on the bottle.
S: Exactly.
(23)
A．To discuss the results of the lab experiment.
B．To answer Bob' s question about the lab experiment.
C．To explain the method of collection by water displacement.
D．To prepare the students to do the lab experiment.
第7题
听力原文：W: Mike, how did you enjoy your trip？ What did you think of Los Angeles？
M: It was all right. I liked it better than I thought I would. The problem is transportation. The bus service is terrible, and they don't have a subway.
Q: What does the man think of Los Angeles？
(15)
A．It is the best city he's ever visited.
B．It was worse than he had expected.
C．It is difficult to get around in the city.
D．The hotel service is terrible in the city.
第8题
M: Did you hear a crash？ That was it. I' m just as clumsy as ever.
Q: What is the problem？
(18)
A．The woman doesn't like jam.
B．The woman forgot where she had left the jar.
C．The man had art accident.
D．The man broke the jar.
第9题
M: I am afraid they are on loan to Michael. If you do not mind waiting, I can give them to you in a couple of days.
Q: What can be inferred from the conversation？
(19)
A．He doesn't have any notes.
B．He doesn't want to lend her the notes.
C．She couldn't borrow the notes from Michael.
D．She has to wait for a few days before she can use the notes.
