A.this opportunity B.a chance C.this time D.aperiod
单项选择题Please leave the key under the door（）you go out.
A.in case B.in the case C.in case of D.in the case of
单项选择题We have kept（）our friendship by writing to each other, so we are true friends.
A.back B.up C.off D.down
单项选择题It（）that I met one of my old classmates on my way home yesterday.
A.took place B.occurred C.broke out D.happened
单项选择题We advised him to give up smoking,（）a lot of exercise.
A.to do B.and to do C.and do D.and doing
单项选择题The refrigerator is（）we must buy some food.
A.bare B.blank C.hollow D.empty
单项选择题These plants are rather difficult（）
A.to look after B.to be looked after C.being looked after D.looking after
单项选择题The act of speaking will also help to improve listening comprehension（）
A.to some way B.in the way C.to some extent D.in the extent
单项选择题They walked（）the woods.
A.up B.down C.through D.over
单项选择题It was well known that Thomas Edison（）the electric lamp.
A.invented B.discovered C.found D.developed
单项选择题After stopping for a few minutes, the bus moved（）to its next stop.
A.forward B.off C.with D.on
