A.seen
B.is seen
C.to be seen
D.having been seen

A.Would he leave
B.If he leaves
C.Was he leaving
D.Were he to leave
A.needn't have scolded
B.needn't scold
C.mustn't have scolded
D.mustn't scold
A.more than to watch
B.than watching
C.rather than to watch
D.more than watching