----Canyouthinkofacaseinwhichtheecologyofanareaisinbala...
问题详情：
---- Can you think of a case in which the ecology of an area is in balance?
---- Sure. You see, ______ an environment is undisturbed, the ecology of the area is in balance.
A．unless B．as C．though D．where
【回答】
D知识点：主语从句
题型：选择题
