to the conference, we have already discussed this problem among ourselves.
After the war, a new school building was put up ______ there had once been a theatre.
The famous scientist grew up _______ he was born and in 1930 he came to Shanghai.
She found her calculator _______ she lost it.
You should make it a rule to leave things _______ you can find them again.
When you read the book, you’d better make a mark _____ you have any questions.