问题 选择题

传粉和受粉的有效时期,通常是(  )

A.开花前,雄蕊成熟时

B.开花后,花瓣萎缩时

C.开花前,胚珠形成时

D.开花后,雌蕊已成熟

答案

答案:D

题目分析:绿色植物结出果实和种子,必须经历开花、传粉和受精的过程。传粉和受粉的有效时期,应该在开花后,不是在开花前,故A、C均不正确;开花后,花瓣萎缩时,会错过传粉有效时期,故B错误;传粉和受粉的有效期在开花后,雄蕊成熟标志着花粉已经成熟,故此题选D。

单项选择题 A1/A2型题
阅读理解

阅读理解。

     As far back as he could remember, Larry had longed to go to Hollywood and become a film star. The

young man's hopes for success were broken again and again,however. Hollywood just did not seem

interesting. When he first came to California, Larry had decided never to give up and return home without

success. Therefore,he kept on trying. Someday,he told himself, his big opportunity would come.

     Larry found a job parking cars for one of Hollywood's big restaurants. His pay was elementary, but since

the guests were kind enough to give him more money, he managed to make a living. One day he recognized

an important film director driving into the parking lot (停车场) and getting out of his car. Larry had recently

heard that the man was ready to make a new picture.

     Larry got into the car and prepared to drive it on into the lot and park it. Then he stopped,jumped out, and

ran over to the director. "Excuse me, sir, but I think it's only fair to tell you that it's now or never if you want

me in your next picture. A lot of big companies are after me."

     Instead of pushing away the boy, the director laughed, then wrote something on a card and handed it to

the young man. "Come and see me tomorrow." Larry got a small part in the director's next film. He was on

his way!

1. Which of the following was Larry interested in? [ ]

A. Working as a waiter.

B. Becoming a film star.

C. Parking cars for film stars.

D. Owing a big company.

2. Why did Larry find a job parking cars? [ ]

A. Because he liked the job.

B. Because the parking lot was near Hollywood.

C. To make a living and wait for the opportunity.

D. To see a lot of film stars and work for them.

3. After reading the story what can we infer (推断) about the film director? [ ]

A. He wanted to laugh at Larry.

B. He recognized Larry at first sight.

C. He was kind and gave Larry a try.

D. He thought Larry would become a star.

4. What does the word "elementary" mean in this passage? [ ]

A. 基本的

B. 充足的

C. 较高的

D. 不达标的

5. "He was on his way" refers to the fact that ______. [ ]

A. he gave up and returned home

B. he began to work towards success

C. he took a journey to Hollywood

D. he had difficulty in playing the small part