The summer vacation is coming．I'm looking forward ___________ it．
Me too．（ ）
A．atB．toC．on
Though Betty and Lily are twins，Betty isn't so ____________ as Lily．（ ）
A．more outgoingB．most outgoing
C．outgoing
David，look at the man in black over there．Can you tell me ____________？
He is an engineer．（ ）
A．who is heB．who he is
C．what he does
I feel upset because I am too heavy．
____________ do more exercise to lose some weight？（ ）
A．Why don'tB．Why notC．Why not to
Mrs．White，can I leave my homework for tomorrow？
I'm afraid not．Don't ___________what you can do today till tomorrow．（ ）
A．put offB．get offC．take off