We were told not to touch the equipment in thelaboratory unless ________.

The news that No．1 Middle School of Qujing was again estimated（评估）the first of the first prize in 2008 ．

We should listen to the weather reportbefore we ___.

, Helen. I think I was a bit rude to you. -________ but don’t do it again.

I usually sleep with the window open it’s very cold.