It is a difficult problem for high school students they can properly use the Internet．
| A．what | B．where | C．when | D．whether |
_____ my English teacher, I have become what I am.
| A．Thanks for | B．Thank to | C．Thanks to | D．Thank for |
Did you find _____ impossible for him to tell the truth?
| A．this | B．it | C．that | D．what |
It isn’t quite _____ that the director will be present at the meeting tomorrow.
| A．sure | B．right | C．certain | D．exact |
The officers narrowly escaped _____ in the hot battle.
| A．have killed | B．to kill | C．to be killed | D．being killed |
The boy is only five years old, but he is quite used _____ the telephone.
| A．to answer | B．to answering | C．of answering | D．by answering |