—Who______ it be that is knocking at the door?
—It ______ be Father, but I’m not sure.
| A．can; must | B．can; may |
| C．must; can | D．may; must |
He always holds a positive attitude _________ anything.
A .with B to C .for D. on
The skin is an essential part of your body and is ____ you feel cold, heat or pain.
| A．where | B．which | C．what | D．how |
---- Tom wants to be another Obama after he graduates from school.
---- That sounds great, but how can he ____ a person like him if he goes on like this?
| A．change | B．turn | C．get | D．make |
If you happen to see the process of cooking in a restaurant, you might see the cook using rubbish oil, which is a common _____ in China nowadays.
| A．sense | B．rule | C．practice | D．activity |
He does help others, but he always expects returns ____. As a result, nobody will accept anything from him.
| A．at no time | B．in no time | C．for no time | D．after no time |