阅读理解。

     A mother and her young son get into a bus. The bus conductor (售票员) comes to them for their

money. The mother says, "I want a ticket (票)to Shanghai", and gives her 5yuan. The conductor looks

at the boy, and says to him, "How old are you, young man? "The mother begins to say, but the conductor

stops her and the boy says, "I’m 4 at home, and 2 in buses."The mother has to give 2.5yuan to the conductor.

1. At first the mother doesn’t give _____ money for the tickets.

A. some

B. any

C. enough(足够的)

2. At last the mother gives _____ to the conductor for her son’s ticket.

A. 7yuan

B. 7.5yuan

C. 2.5yuan

3. The mother gives the conductor _____ in all(总共).

A. 10yuan

B. 7.5yuan

C. 5yuan

4. The boy is _____ in fact(事实上).

A. 2

B. 4

C. 7

5. The mother is _____ .

A. not honest(诚实)

B. honest

C. very clever

森林群落的垂直结构是指群落的______。