The flu is believed by viruses that like to reproduce in the cells inside the human nose and throat.
| A．causing | B．being caused | C．to be caused | D．to have caused |
Having checked the doors were closed, and ___ all the lights were off, the boy opened the door to his bedroom.
| A．why | B．that |
| C．when | D．ours |
It is none of your business __________ other people think about you. Believe yourself.
| A．how | B．what |
| C．which | D．when |
You can only be sure of __________ you have at present; you cannot be sure of something __________ you might get in the future.
| A．that; what | B．what; / |
| C．which; that | D．/; that |
A warm thought suddenly came to me __________ I might use the pocket money to buy some flowers for my mother’s birthday.
| A．if | B．when |
| C．that | D．which |
These shoes look very good. I wonder __________.
| A．how much cost they are | B．how much do they cost |
| C．how much they cost | D．how much are they cost |