The man called his professor for help because he couldn’t solve the problem by _________.

Will she ________ go with you? –Well, I’m not sure.

Could you tell me ________?—Sorry. I don’t know. I didn’t attend the meeting.

I’d prefer ______ in the office rather than ______ at home watching TV.

It’s very convenient______us to buy train tickets now because we can buy themeither fromthe station or on the internet.[ ]