—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 |
Why are you always making the same mistake? Think of _____ I told you.
| A．that | B．when | C．how | D．what |
The mountain village is my hometown. I spent _____ merry night there when I was young.
| A．a great many | B．plenty of | C．many a | D．a great deal |
Those _____ to go to the exhibition should inform the office.
| A．not wanting | B．who not want | C．not wanted | D．are not want |
___ he was ill, I was expected to take his place greatly surprised me for I didn't have much working experience.
| A．If | B．That if | C．That | D．If that |
Only after a baby seal is pushed into the sea by its mother ___ to swim.
| A．how will it learn | B．it will learn how |
| C．will it learn how | D．and it will learn how |