When he was working there he caught a serious illness from _____ efforts he still suffers. 
#72572
A
which
B
that
C
whose
D
what
推荐题目
On the table she found a piece of paper _______ some confusing symbols.
#73639
A
which was written
B
that was written
C
on which were written
D
on that was written
She wrote a month ago, ______ we’ve heard nothing. 
#73446
A
since when
B
before which
C
since that
D
after which