Scientists are convinced _____the positi
题型:选择题
问题:
Scientists are convinced _____the positive effect of laughter _____physical and mental health.
A.of ;on
B.by; in
C.of ; at
D.on ;at
Scientists are convinced _____the positive effect of laughter _____physical and mental health.
A.of ;on
B.by; in
C.of ; at
D.on ;at