If his parents are convinced ______ the fact that his son always focuses his mind _______his study. 
#28556
A
of; on
B
of; at
C
by; to
D
on; at
推荐题目
He is ____our teacher; he is also our best friend. 
#26385
A
less than
B
rather than
C
more than
D
better than
I met an old friend __________ on the train yesterday.[
#26650
A
by chance
B
on purpose
C
in fact
D
in return
 Psychological studies show that some people are quick-tempered _____.
#28355
A
at heart
B
on purpose
C
in person
D
by nature