is hard is to do good all one’s life and never do anything bad.
| A．That | B．What | C．All | D．Which |
I couldn't understand ______ at the poor child.
| A．you to laugh | B．you laugh | C．why laugh | D．you laughing |
We can't understand ______ a decision until it is too late.
| A．him to postpone to make | B．his postponing to make |
| C．him to postpone making | D．his postponing making |
Alien said that his trip was _______.
| A．interested | B．interest | C．interesting | D．of interest |
---- What do you think about English? ---- It's a difficult language _____.
| A．speaking | B．to be spoken | C．to speak | D．spoken |
I really don’t know ____ .
| A．to swim | B．how to swim | C．to swim how | D．how swim |