How long have you known the doctor ? — hehelped me three years ago.

下列有关文学常识的表述正确的一项是

, is this your ruler—Yes, it is. Thank you.

I can’t connect my computer to the Internet. There must be _______wrong with it.

Nowadays, teenagers seldom do any housework at home.— No, they don’t. Doing homework ______ most of their time.