A. for which B. in which

C. of which D. from which

17. Yesterday she sold her car, ______ she bought a month ago.

A. whom B. where C. that D. which

18 I'll give you your friend's home address, I can be reached most evenings.

A. which B. when

C. whom D. where

19 . They will fly to Washington, ___ they plan to stay for two or three days.

A. where B. there C. which D. when

20 We went through a period ___ communications were very difficult in the rural areas.

A. which B. whose

C. in which D. with which