单项选择题

A．It affects the growth of trees.
B．It has been increasing since the Ice Age.
C．It is determined by the chemicals in the air.
D．It follows a certain cycle.
<上一题 目录 下一题>
热门 试题

单项选择题
A．Critical.B．Serious.C．Skeptical.D．Casual.
A．Critical.
B．Serious.
C．Skeptical.
D．Casual.
单项选择题
A．It will increase the amount of unpleasant odors from vehicles.B．It will eventually destroy the ozone layer.C．It will reduce the amount of pollutants in the air.D．It will reduce the cost of running large vehicles.
A．It will increase the amount of unpleasant odors from vehicles.
B．It will eventually destroy the ozone layer.
C．It will reduce the amount of pollutants in the air.
D．It will reduce the cost of running large vehicles.
相关试题