恢复中国在联合国合法权利的时间是[ ]
A.1970年
B.1971年
C.1972年
D.1979年
答案:B
在生态系统中各种生物的数量和所占的___________总是维持在相对稳定的状态,这种现象叫___________。
Part of the reason Charles Dickens loved his own novel, David Copperfield, was ________ it was rather closely modeled on his own life.
A.what
B.why
C.that
D.whether