The glass doors have taken the place of the wooden ones at the entrance,in the natural light during the day.
| A． | to let | B． | letting | C． | let | D． | having let |
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 |
You needn’t have ________ the speaker when he was speaking; there was enough time afterwards for you to ask questions.
| A．affected | B．interrupted |
C．involved | D．disturbed |
It’s helpful to put students in a situation _______ they can learn how to cooperate with each other.
| A．that | B．when |
C．which | D．where |
Lucy is a very optimistic girl. ______ she is faced with difficulties, she always sees the bright side.
| A．Every time | B．Now that |
C．As soon as | D．On condition that |