What do you think makes a good doctor—As doctors, they can’t be ________ careful. They must have perfect medical skills.

I didn’t know your mobile phone number; otherwise I____ you the second I got to Changsha.[ ]

They stayed with me three weeks,______ they drank all the wine I had[ ]

Look out when crossing the road, _____ you may be hit by a car

We have to ask them to ____talking in order that all people present could hear us clearly.