问题 选择题

受精的鸟卵在雌鸟体内开始发育,但鸟卵产出后就停止发育,原因是外界( )

A.具有阳光

B.具有空气

C.温度太高

D.温度太低

答案

答案:D

题目分析:鸟卵的孵化受温度的影响。在生殖季节,雌雄鸟交配,精卵结合在雌鸟体内结合成受精卵.受精卵在鸟体内就已经开始发育,当雌鸟产下受精卵后,由于外界温度低于亲鸟的体温(42度),胚胎停止发育,需要由亲鸟孵化才能继续发育。

故D符合题意。

阅读理解

阅读理解。

     Driving a large truck over mountain roads is not the usual way that a schoolteacher begins her day-

especially if she is a preschool teacher. But Mrs. Beth Miller does this five days every week. Her unusual

schoolhouse on wheels is actually a truck. The back of the truck has been made into a classroom in order

to carry the advantages of modern education to remote areas of the state of West Virginia. In many rural

areas of this state it is impossible for small children to go to regular schools because of the many hills and

valleys of Appalachian Mountains.

     The purpose of the schoolhouse on wheels project is to develop basic skills and social behavior in

children three to five years of age. This is done through games, exercises, toys and simple handcrafts. The

schoolhouse on wheels concept also teaches the young children to recognize 300 to 400 words on the printed

page. This is a great advantage in helping the pupils to learn to read when they begin regular school. In its

three-year history the project has helped about 350 children in an area made up of five counties, an area of

20 000 square kilometers. The schoolhouse on wheels is part of the Appalachian Educational Laboratory, a

research effort paid for by the government. Besides the mobile classroom, other parts of the program include

lessons by television and visits to the homes of the students. The technique is very effective, and one teacher

can do the work of seven in a traditional educational system. As a result the program costs about 50% less

than the regular kindergarten.

     All these advantages of the schoolhouse on wheels have made both parents and school officials happy.

West Virginia plans to increase the program and to include it in the public school system so that more than

4500 preschool children can have this valuable learning experience.

1. Mrs. Beth Miller usually _____.

A. walks to begin her work

B. drives a large truck to begin her work

C. drives her car to the school

D. carries the classroom to the school

2. Children in many rural areas of West Virginia cannot go to regular schools because _____.

A. large trucks cannot go in mountainous areas

B. there are no schoolhouses on wheels there

C. there are many hills and valleys there

D. preschool teachers don't like to work there

3. The best title for this passage is _____.

A. Schoolhouse on wheels

B. West Virginia

C. Effective educational system

D. Educational laboratory

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