The math problem is so hard. I really don’t know .
| A．how to do it | B．how to do | C．what to do it | D．where to do it |
I’m going to London and my sister is going _______.
| A．also | B．either |
| C．as well | D．as well as |
You _______ take the book out of the library. You can only read it here.
| A．may not | B．needn’ |
| C．mustn’t | D．shouldn’t |
The dirty water in the river _____ many problems in the past ten years.
| A．creates | B．created |
| C．was creating | D．has created |
_______, let’s make a plan for the holiday.
| A．After all | B．All the time |
| C．For a time | D．First of all |
Liu Xiang’s parents ________ him to do sports after class.
| A．asked | B．was asked |
| C．allowed | D．was allowed |