______ environmental damage is done, it takes many years for the ecosystem to recover.
| A．Even if | B．If only | C．While | D．Once |
Much to our ____, he didn’t do what he had promised.
| A．satisfaction | B．dissatisfying |
| C．satisfying | D．dissatisfaction |
She _____ an old friend of hers yesterday while she was shopping at the department store.
| A．turned down | B．dealt with | C．look after | D．came across |
A few _____ looked at him curiously when he suddenly stopped and burst out crying.
| A．passers-by | B．passer-bys |
| C．passers-bys | D．passer-by |
Changbai Mountain is one of China’s largest nature reserves, and has many ____ plants and animals.
| A．various | B．rare | C．major | D．common |
Mrs. Green went back home hurriedly, where her two little twins were crying, _____ they were hungry.
| A．said | B．saying | C．to say | D．having said |