—Have you been to the Great Wall?
—Perhaps not in my memory.________，it might have been during my early childhood.
| A．If any |
| B．If ever |
| C．If once |
| D．If not |
—Lucy, go do the washing please.—_______ I just did it yesterday.
| A．It’s your turn. | B．It’s up to you. | C．So what? | D．With pleasure. |
He is very_____; it is impossible to talk him into doing anything he doesn’t want to.
| A．stubborn | B．curious | C．skeptical | D．gracious |
It was only then ______ I began to have doubts about whether my story had ever been told.
| A．when | B．Since | C．that | D．yet |
The secretary worked late into the night, ______ a long speech for the president.
| A．to prepare | B．prepared | C．preparing | D．to be prepared |
There is no doubt _______ nearsightedness is a serious problem among the youth of our country.
| A．/ | B．which | C．whether | D．that |