We have been told that under no circumstances _______ the telephone in the office for personal affairs. [ ]

－ Henry isn’t quite himself today. He seems to be so tired.－ He said he had worked on his project ________ the whole night.

It was in the lab _____ was taken charge by Professor Wang ______ they did the experiment.

We ___________ when the teacher camein.

Listening to loud music at rock concerts ________ caused hearing loss in some teenagers.[ ]