I think it ______that one have a good command of English if one wants to be engaged in international trade.[ ]

I’m sorry my memory has ______ , for the prices of the things have gone up.

You’d better check your bills_____ any error when shopping in the supermarket[ ]

Is it for two months ______ they h

The dog has a(n) _______ sense of smell while the rabbit has a sharp sense of hearing.