Why_______ the modern city with us ?

Don’t ______ so often. It’s bad for your health.

When did you ___________ the army?

—I miss my mother very much. She has gone abroad on business for nearly a year but luckily she will be back in a week. —Pardon? I ______ something else just now. ________ will she come back?

 --Mike, can you tell us something about our new teacher? -- Oh, sorry. I know nothing because I     _ him before.