---Is your uncle still smoking?
---Yes. It’s nearly five years _______ he smoked.

---I wonder if he ______ us in the discussion tonight.
---I believe if he ________ his homework, he will join us.

I don’t know _____ he will come tomorrow. _____ he comes, I’ll tell you.

______both of us failed to pass the driving test,______ we learned much about driving.

Tim will call me as soon as he______ my package.

_______ well you drive, you must drive carefully.

My uncle has been taught in this school _______ he was twenty years old.

— May I go to the concert with you?
— I’m afraid not ____ you have a ticket, because I have only one.

______it's difficult to make her dream come true，she never gives up.

Scientists say it may be a few years ______it is possible to test the new medicine on patients.