We are roommates for 3 years and never once __________ .
A. we have quarreledB. have we quarreled
C. do we quarrelD. did we quarrel
I will never forget the park __________ I spent so many happy hours there with my parents last summer .
A. whereB. because
C. whichD. so
In fact , the hazy weather problem is so severe now that it has aroused __________ nationwide concern about __________ environmental pollution .
A. / ; /B. / ; the
C. a ; /D. a ; the
– I spent three hours buying a train ticket at the railway station the other day .
-- Why ? You __________ one on the Internet or by phone .
A. could have boughtB. must have bought
C. would buyD. should buy
The newly married couple couldn’t afford to buy a new car ; __________ , they bought a used one .
A. howeverB. instead
C. otherwiseD. still
– Well , Jack , I am sorry that I have to leave .
-- __________ . Let’s email often .
A. Enjoy yourselfB. That’s for sure
C. So am ID. Keep in touch
