第4题: [单项选择]What is the government laboratory trying to do A. Collect ash tree seeds for experiment. B. Preserve the healthy ash tree seeds. C. Set up a new seed bank for research. D. Develop a new breed of ash tree. 参考答案:B 答案解析:[解析] 短文说，实验室对种子进行检查和照X-ray，确保没有钻孔虫的受精卵，只有最好的被保存起来。故答案是B。 [点睛] 从选项可以初步猜测题目与措施有关。听到“Only"表明文章要提出特殊
A. at a stretch B. to perfection C. with one accord D. in justification 参考答案:C 答案解析:代表们一致投票要求修改章程以满足业务扩展的需要。本题是考查介词词组的用法。at a stretch“不停的，连续的”to perfection“恰到好处的，尽善尽美的，完全的”；with one ac
