外语选择题！

1  the missing boys were last seen ---------near the river

A playing   B to be playing  C play  D to play

2  --------?

    he must be professor wang"s

A do you suppose where he can be

B where do you suppose he can be

please  tell me why!  thanks!

1  the missing boys were last seen ---------near the river

A playing  

 see sb.doing sth看到某人正在做某事的被动形式 be seen doing sth.

2  --------?

    he must be professor wang"s

 B where do you suppose he can be

do you suppose, do you think等是插入语。放在特殊疑问词之后，句子用语陈述序

A  是看到他正在河边

B   特殊疑问句句式。