In the west, people make _______ a rule to send Christmas present to their relatives and friends.
| A．this | B．that |
| C．it | D．the following |
It is reported that this kind of vegetables _ a lot of vitamins C.
A. contains B. includes C. holds D. keeps
______ time went by , Herbert could finish all the maths exercises in class.
| A．With | B．As | C．while | D．Since |
Lots of the scientists in our country are working hard to ____the planet Mars .
| A．cover | B．search | C．discover | D． explore |
Look at the notice . You are not allowed ____ the gymnasium without permission.
| A．to enter | B．enter | C．entering | D．for entering |
How are you going to _______ such problems?
| A．do with | B．deal with |
| C．deal | D．do up |