He wrote a letter ________ he explained what had happened in the accident.
A. what B. which
C. where D. how
He may win the competition, ________ he is likely to get into the national team.
A．in which case B．in that case
C．in what case D．in whose case
There is no simple answer, ________ is often the case in science.
A. as B. that
C. when D. where
Nowadays people are more concerned about the environment ________ they live.
A. what B. which
C. when D. where
____is often the case with children, Amy was better by the time the doctor arrived.
A. It B. That
C. What D. As
John invited about 40 people to his wedding, most of ________ are family members.
A．them B．that
C．which D．whom
