群落演替过程中，物种多样性最丰富的阶段是[ ]
A．灌木阶段
B．草本植物阶段
C．苔藓阶段
D．森林阶段
答案：D
The experiment shows that proper amounts of exercise,if ___________ regularly, can improve
our health. [ ]
A. being carried out
B.carrying out
C. carried out
D.to carry out
大黄、当归炮制的适宜方法是
A．酒炙
B．盐炙
C．蒸法
D．煮法
E．醋炙
