Scientists are convinced_____the positiv
题型:选择题
问题:
Scientists are convinced_____the positive effect of laughter_____physical and mental health.
A.of; at
B.by; in
C.of; on
D.on;at
Scientists are convinced_____the positive effect of laughter_____physical and mental health.
A.of; at
B.by; in
C.of; on
D.on;at