— I don’t know next.
— Let’s ask our teacher for help.
| A．what to do | B．what should I do |
| C．how to do | D．how I should do |
He didn’t study hard, so he was afraid ______ in the exam.
| A．fail | B．to fail | C．failing | D．failed |
I had some problems _____ my homework.
| A．to finish | B．finishing | C．finishes | D．finish |
Can you learn English ________ chatting on the Internet?
| A．in | B．with | C．by | D．for |
He thinks _____ history about Chinese is very important.
| A．studied | B．studying | C．studies | D．study |
How many states _______ the United States? Fifty.
| A．turn up | B．make up | C．end up | D．give up |