Where is Tom —-He’s left a(n) _____ saying that he has somethingimportant to do.

The dog ____attacked passers-by and therefore was kept on a chain by the owner.

Mr Black with his wife _____visiting China now.

(2013·高考新课标全国卷Ⅱ)A serious study of physics is impossible________some knowledge of mathematics

Cathy wonders if her teacher _______ to herhouse. If she _______, what will she say to her parents