Since the opening and reform policy, China a boom in its economy.
A. enjoys B. has been enjoying C. enjoyed D. having enjoyed
private cars are bringing us conveniewce, they may also cause traffic accidents and pollution.
A. When B. Since C. while D. As
Nowadays, many people walk to work, Copenhagen（哥本哈根）Conference calling for living a low-carbon life to cope with global warming.
A. in relation to B. in terms of C. in apposition to D. in response to
He has been working hard day and night, which, of course, his tiredness.
A. accounts for B. answers for C. applies for D. stands for
Could I do some explanations? I to call on you last night, but somebody came to see me just when I was to about leave.
A. would intend B. intended C. had intended D. was intending
His parents, , didn’t look after him very well—the elbows of his jacket and his boots were badly worn out.
A. generally B. apparently C. gradually D. precisely
