问题 单项选择题

下列有关突触的叙述中,正确的是()

A.神经元的树突末梢经过多次分支,最后每个小枝末端膨大形成突触小体

B.突触小体可以与其他神经元的细胞体或树突等通过一定方式形成突触

C.在光学显微镜下可以观察到突触的亚显微结构

D.前一个神经元的突触前膜和后一个神经元的突触后膜共同构成突触

答案

参考答案:B

解析:一个神经元的轴突末梢经过多次分支,与下一个神经元的树突或者细胞体形成突触,即一个神经元有多个突触,A错误, B正确;由于受放大倍数的限制,在光学显微镜下不能观察到突触的亚显微结构,C错误;前一个神经元的突触后膜和后一个神经元的突触前膜共同构成突触,D错误。考点:本题考查突触的的知识。意在考查能理解所学知识的要点,把握知识间的内在联系的能力。

阅读理解

阅读理解。

     How many kinds of shapes (形状) can you name? If something is round, what do you call it? You call it

a circle. What can you see around you that looks like a circle?

     Another shape is square. A square has four sides. Each side is the same length (长度). A square has four

corners called right angles (直角).

     A triangle is also a shape. The prefix "tri" on the base word "angle" means "three". A triangle always has

three sides and three angles.

     All the pages of your textbooks have four square corners, but the pages are not square. Can you tell why

not? It is because the sides of each page are longer than the ends. Shapes like this are rectangles. You can say

that they are rectangular shapes.

      If you are given a piece of paper which is a rectangular shape, can you make the paper into a square? The

answer is "Yes", and it seems not so difficult. Now fold the square. What shape have you got? Do you think

it's very interesting?

1. You usually learn the knowledge discussed in this passage in _____ classes.

A. chemistry

B. math

C. history

2. Picture _____ is a rectangle.

A.  B.  C.

3. Picture _____ shows the right marks of"side & end" according to the passage.

A.  B.  C.

4. Fold a square in the way of the picture shown on the right, you may get a shape of _____.

A. square

B. rectangle                                       

C. triangle

5. In this passage, we've learned about _____ kinds of shapes.

A. three

B. four

C. five

单项选择题