It is good manners to eat up _______is left in your plate.
A. that B. what C. which D. all
Can you explain ________ the sun goes down in the west?
A. why is it that B. why it is that C. how it is that D. how is it that
A huge amount of oil was spilt on the East Sea, the causes of ______ are still under investigation.
A. it B. that C. which D. whom
--- Has James finished his report on his Enquiry Learning yet?\
---- I’m not sure. He _____ on it last week.
A. was working B. has worked C. worked D. had worked
If you are traveling_ the customs are really foreign to your own，please do as the Romans do.
A. in which B. what C. when D. where
you may have, you should gather your courage to face the challenge.
A. However a serious problem B. What a serious problem
C. However serious a problem D. What serious a problem
