What has happended to these kids?They don't keep silent in class even for a short time .---Oh,you know,_____be very active. ould n.C.woould.D.have to.
热心网友
n---Oh,you know,they can be very active.这里表现出的是理解同情的口吻，用 can 最合适。 ould 表现出的不是认同，适用于反驳的口气， Hey, they are kids, they should be very active.
热心网友
A 如果说理由 大概是 “他们应该很活跃”
热心网友
a
热心网友
a,表示很惊讶