—When did his parents pass away?
—It was on April 14th________the earthquake hit Yushu County.
A.what B.that
C.which D.when
—When did his parents pass away?
—It was on April 14th________the earthquake hit Yushu County.
A.what B.that
C.which D.when
D 考查定语从句。此句看似是一个强调句型,但根据对话提供的情景,上句问的是“时间”,下句只要回答出时间就行了,故后面是when引导的定语从句。