读对话，判断正(T)误(F)。

A: Do you have new teachers, Tom?

B: Yes.

A: Who are they?

B: Mr. Lin and Mr. Sun.

A: Are they young?

B: Mr. Lin is young, but Mr. Sun isn't.

A: Is Mr. Lin a university student?

B: Yes, he's very funny.

A: Is Mr. Sun strict?

B: Yes, and we all like them very much.

( ) 1. Tom has two new teachers.

( ) 2. Mr. Sun isn't strict.

( ) 3. Mr. Lin is young. Mr. Sun is old.

( ) 4. Mr. Lin is funny.

( ) 5. Tom likes his new teachers very much.

下列关于群落演替的说法不正确的是（）

A.在群落演替过程中，群落的物种构成不断地发生着改变

B.群落演替的根本原因在于群落内部，不受外界因素的影响

C.初生演替和次生演替的主要区别是演替的起始条件不同

D.在群落演替过程中种群总数开始是逐渐增多而后趋于稳定