Hardly had the employees ________with their work when the rain stopped

Have you ________ to your friend Larry’s letter—No，not yet.I’m quite busy these days.

The accident happened on such an eveningwith strong windsby heavy rain.

When did you get to know the professor over there? —It was at the work shopwe did reserch to gether two years ago.

What does the notice on the wall say? — “No person _____ take books out of the reading room; otherwise he _____ be fined.”