_____ many times, but he still doesn’t know how to operate the machine properly.

What’s wrong with your coat?——Just now when I wanted to get off the bus, the man next to me _______ on it.

The twins are so much alike that it is difficult to tell one from________.

The presidents of China and Russia had ____ interview a short time ago .— And it was ____ great success. .

When the baby pandas see the keepers, they run over with excitement.