Modern science has given clear evidence __________ smoking can lead to many diseases.
A. what
B. when
C. that
D. where
__________ the English evening will be held has not yet been announced.
A. Where
B. Who
C. What
D. Whom
It's strange __________ there are no lights on.
A. who
B. that
C. where
D. whoever
She will give __________ needs help a warm support.
A. whoever
B. wherever
C. whenever
D. however
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