时间状语从句可由when，whenever， while，before，after，until，till，since，now that，once，as soon as等连词引起：
Let’s wait until(till)the rain stops.
She comes to talk to me whenever she feels lonely.
As I talked，I gained some confidence.
Now that I have come back,I want to help you both.
Once the train is moving，there is no way to stop it.
2.由every time，the moment等词引起的从句也可以用作状语
Every time I catch a cold，I have pain in my back
Stormy applause broke forth the moment she appeared on the stage
He had impressed me that way the first time I met him.
Be sure to call on us next time you come to town.
The machine will start instantly you press the button.
I’ll give you an answer immediately I’ve finished reading your report
Directly he uttered these words there was a dead silence.