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

填空题
O
单项选择题
A．She’s going to New York.B．She’s going to Chicago.C．She’s going to Washington.D．She’s going to San Francisco.
A．She’s going to New York.
B．She’s going to Chicago.
C．She’s going to Washington.
D．She’s going to San Francisco.
相关试题