_ we left the building that Irealized how dangerous the situation had been.

Tom, who is always shy in public, has made some friends at school, ______ has pleased his parents.

I still haven’t made any progress in writing an English article．— ．How can you write a passage when you don’t understand the words.

I live at school. So I often go home _______Friday afternoon.

John, what’s this _______ English — It’s a computer.