题目

If it ___ rain, we ___ get wet. A. is to, should                    B. were to, would        C. were going to, would                D. was going to, should   答案：B关于群落的说法正确的是 A．弃耕的农田不能演替形成树林 B．在群落演替过程中，最先出现的动物是植食性动物 C．在群落演替过程中，灌木取代草本的主要原因是草本植物低等 D．任何情况下，人类活动对群落的影响均超过其他所有自然因素