If you ______ stop smoking , you can only expect to have a bad cough .

I _____glasses since I was in primary school and I hate them. They make me look like a bookworm.

It is said that the old coins ______ under the earth for about 100years by the time they were discovered.

Although the causes of cancer ________, we do not yet have any practical way to prevent it．

Joseph __________to evening classes since last month, but he still can’t say “What’s your name?” in Russian.