Question

【题目】______ environmental damage is done，it takes many years for the ecosystem to recover．

A. Even if B. If only

C. As if D. Once

Answer 1

【答案】D

【解析】一旦环境破坏被造成，它将会法非好多年让生态系统恢复。根据句意选D 一旦而 A即使 B只要 C好像，均不符合题意。