Question

【题目】用when/while填空。
（1）He was listening to music he was riding his bike.
（2）I was waiting at the lights I saw the boy fall off his bike.
（3）I was walking in the street I saw the accident happen.
（4）The driver was talking on his mobile phone he was driving.

Answer 1

【答案】
（1）while
（2）when
（3）when
（4）while
【解析】when和while的区别：when引导的从句可以用一般时态也可以用进行时态；while引导的从句只能用进行时态。when有两个意思：①当……的时候，②这时，那时；while正当……的时候。
（1）句意：他正骑自行车的时候听音乐。前后都用进行时态，用while。
（2）句意：我正在等红灯，这时我看见那个男孩从自行车上摔下来。表示这时，用when。
（3）句意：我正在街上走，这时我看见一起事故发生了。表示这时，用when。
（4）句意：司机打电话的时候正开着车。前后都用进行时态，用while。