It is well-known that humans differ _____ other mammals in their ability to speak.[ ]

This kind of metal ______ well，and therefore the metal stick ______ into halves easily.[ ]

We’d better try to ____ with the experiment, I think. Now let’s ____ with it.

It’s time for supper now. Let’sit.

________________ strong country our motherland is! We are so proud of it.— Yes. It is developing very fast.