Not until he left his home ______ to know how important the family was for him.
| A．did he begin | B．had he begun | C．he began | D．he had begun |
Cindy shut the door heavily and burst into tears. No one in the office knew ______she was so angry.
We can never expect_______bluer sky unless we create_______less polluted world.
| A．a; a | B．a; the | C．the; a | D．the; the |
The visit _____ to Guilin is worth remembering for ever.
| A．paid | B．paying | C．to pay | D．being paid |
Some children want to challenge themselves by learning a language different from their parents speak at home.
| A．what | B．that | C．which | D．one |
______, and everything will be all right.
| A．Hold off | B．Hold on | C．Hold out | D．Hold up |