成人本科學位英語單項選擇題每日一練(2020.10.03)

來源：考試資料網(wǎng)

1 Be careful,（）you'll fall down.

2 The problem（）when the students refused to do their homework.

3 （）good health, one can achieve anything.

4 The aircraft vanished without（）

5 Technology is to the development of the modern society a matter of（）importance.