1 . As the evidence began to a______, experts from the Zoo felt obliged to investigate. （根据首字母单词拼写）

2 . As we__________(accumulate) more devices, however, we didn't throw out our old ones. (所给词的适当形式填空)

3 . As people________（积累更多财富）, they tend to spend a greater proportion of their incomes. (根据汉语提示完成句子)

4 . For the sake of our human beings’ health and happiness, posters were put up around the community to _________public concern over environment protection.

A．accumulate

B．preserve

C．cause

D．arouse