What________is the most helpful invention？
| A．you think |
| B．I think |
| C．you do think |
| D．do you think |
It usually takes my mother forty minutes _______ the house.
| A．clean | B．to clean | C．cleans | D．cleaning |
There is _____ “u” and _____ “r” in the word “your”.
| A．a, a | B．an, an | C．an, a | D．a, an |
Don’t throw plastic bags towards the animals in the zoo.
| A．All right. | B．Nothing. |
| C．Not at all. | D．I’m glad. |
---Is that Mr Smith?
---It __________ be him. He is in New York on business these days.
| A．may not | B．needn’t | C．can’t | D．mustn’t |
The boy looked __________ because he didn’t pass his maths test.
| A．sad | B．sadness | C．saddest | D．Sadly |