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．where |
This problem may lead to more serious ones if _______ unsolved.
| A．making | B．remained | C．keeping | D．left |
The Chinese language _______ many Western languages _______ it uses characters which have meanings and can stand alone as words.
| A．different from; in that | B．differs from; in which |
| C．differs from; in that | D．is different from; in which |
The English language _______ the rules and vocabulary each group of people brought to Britain with them.
| A．is consisted of | B．is made up of | C．composed of | D．consisting of |
On average, these footprints are 14 to 18 inches long, 5 to 9 inches wide and much larger than _______ of a human.
| A．that | B．it | C．those | D．one |
Young as he is, David has gained _______ rich experience in _______ society.
| A．the；the | B．a ； / | C．/ ； / | D．/；the |