I think _______ a foreign language is not easy. You should _______ it often.
| A．to learn; to practice | B．learning; practice |
| C．learn; practicing | D．learns; to practice |
I don’t know _____ or not he will come . _______ he comes , I will call you .
| A．whether ; If | B．whether ; Whether | C．if ; If | D．if ; Whether |
The robot needs _______ once a month. And we will check it for you for free.
| A．to check | B．checked | C．checking | D．to checking |
We didn’t know how to find them because they didn’t tell us _______.
| A．which room did they live | B．which room they lived in |
| C．which room they lived | D．which room did they live in |
In order _______ his English，he joined an English club.
| A．improving | B．to improve | C．improves | D．improve |
Don’t make the students _______ this or that . They are busy.
| A．to do | B．do | C．doing | D．done |