单项填空（4题）
1.—Hello! Is _____ Mary?
—No, _____ is Sally.
A.she; it；B.that; this；C.this; that；D.you; it
2.Bill's sister has _____ MP4.
A.an；B.the；C.不填；D.a
3.What's it in the picture? I _____ it's a model plane.
A.know；B.think；C.see；D.say