When did you come here?

你什么时候到这儿来的?

When the delayed flight will take off depends much on the weather.

延误的航班何时起飞主要取决于天气状况。

I’d like to know when they’ll come back.

我想知道他们什么时候回来。

This was the moment when I made my decision.

这是我作出决定的时刻。

The last time I went to Scotland was in May, when the weather was beautiful.

我上次去苏格兰是在五月份，那时的天气好极了。

When I was a child, my family lived in Beijing.

我小的时候，全家人都住在北京。

When in Rome do as the Romans do.

入乡随俗。

We were about to go for a picnic when it began to rain.

我们正要去野餐，这时天突然下起雨来。

Jack was working in the lab when the power cut occurred.

停电时，杰克正在实验室里工作。

He had just fallen asleep when the telephone rang.

他刚睡着电话就响了。

Turn off the switch when anything goes wrong with the machine.

如果机器发生故障，就关上开关。

Why use metal when you can use plastic?

既然能用塑料，为什么要用金属呢？

She claimed to be 18, when I knew she was only 16.

她自称18岁，可是据我所知她才16岁。

Till when can you stay?

你能待到什么时候？

We came back on Tuesday, since when we have been working in the repair shop.

我们星期二回来的，从那时起就一直在修理车间工作。