--- _______ I come back before 6 o’clock?---No，you _______．But you _______ be back later than 7 o’clock．

 ---Could you please come to the museum with me this afternoon?---Sorry, I ______ . I have to take a piano lesson at 2 pm.

They can hardly move at all, _____________?

(2013·安徽师大附中高三七模)Don't use water to put out the fire if oil catches fire. As is known, oil ________ float on water.

- Tom, where is your father?- I’m not sure. He _______ in his office.