She will never forget the days ______ she spent in Beijing.
A. when
B. what
C. which
D. why
This is the subject ______ we have talked a lot.
A. to which
B. about which
C. that
D. which
Physics is the subject in our school _______ every student is interested.
A. which
B. what
C. that
D. in which
I'll never forget the day _______ she said goodbye to me.
A. that
B. what
C. which
D. when
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