The train leaves at six tomorrow morning.
When does the bus star? It stars in ten minutes.
2）倒装句，表示动作正在进行，如：
Here comes the bus. = The bus is coming.
There goes the bell. = The bell is ringing.
3）在时间或条件句中。
When Bill comes (不是will come), ask him to wait for me.
I‘ll write to you as soon as I arrive there.
4）在动词hope, take care that, make sure that等后。
I hope they have a nice time next week.
Make sure that the windows are closed before you leave the room.