Whatever is left over may be put into the refrigerator，________ it will keep for two or three weeks.(2011·安徽)

It’s clever________ Amy to make a birthday cake, but it’s hard _____ me to do that.

__ Any suggestions? __ You’d better ______________ the last sentence as it is rather misleading.

David asked his nephew to ______ his bag while he headed for a drink at the airport.

________ it is from our own planet Earth to Mars!— Yes, it takes months to travel to Mars by spacecraft.