It was ____ the old worker came that we ____ the experiment.

Could you tell me____—Sorry，I have no idea.

You’ll fail in the English test ________ you work hard at it.

Even though it is at least 20 years _____ we got to know, I can’t forget the scene_____ we were introduced to each other

I am terribly sorry. I have dropped your phone.— ________. Look, it still works.