Question

(1)單項選擇

The research is so designed that once ________ nothing can be done to change it.

[　　]

A．begins

B．having begun

C．beginning

D．begun

(2)完成下面句子

過馬路時一定要遵守交通規則。

________ the street, be sure to ________ the traffic rules.

Answer 1

答案：
解析：

解答：(1)D;(2)When crossing，follow

提示：

名師導引：題1中once begun等同于once the research is begun；題2中過馬路用when +crossing作狀語；follow表“遵守”。