We can never forget the days the two astronauts in spaceship worked together and the days

问题补充：

We can never forget the days the two astronauts in spaceship worked together and the days we spent together.

A. which; when

B. when; which

C. what; that

D. on which; when

答案：

A. which; when

(答案→)B. when; which

C. what; that

D. on which; when

解析：句意：我们永远不会忘记在宇宙飞船中的两名宇航员一起工作的情形，也永远不会忘记我们在一起的日子。选择定语从句的关系词关键在于看关系词在从句中作什么成分。第一个空，关系词在从句中作时间状语，故用when或on which； 而第二个空，关系词在从句中作spent的宾语必须用which或that。综合两个空，只能选B。