Helen plays the piano well her favourite instrument is the violin.A. soB. yetC. orD. for

问题补充：

Helen plays the piano well, her favourite instrument is the violin.

A. so

B. yet

C. or

D. for

答案：

A. so

(答案→)B. yet

C. or

D. for

解析：考查连词用法。A因此；B然而；C或者；D因为。根据句意可知上下文是转折关系。句意：Helen的 钢琴弹的很好，然而她最喜欢的乐器是小提琴。