It was not until he came back _____ he knew the police were looking for him.[ ]

I didn’t________my primary school classmate Jane until I listened to her selfintroduction.[ ]

Our headteacher is very strict_____us and he is also very strict ____his work .

In the company many workers think that the rules are in need of revision (修订).

Europe has achieved more in controlling the AIDS virus than Asia in the past ten years, ______ the number of people infected with the virus is going up sharply[ ]