In American there are more households with pets than ____ with children.

—Why didn't Mr.Smith arrive on time for the meeting?—He must have been ________ on his way here in the traffic jam.

(2013 ·安徽名校联考Ⅰ)—May I speak to Mr.Smith?—I am afraid not.He is at a meeting now.It's not ________.

Liu Xiang’s talent for running and his ability to learn from his experiences________greatly to his many successes in sports.

 This printer is of good quality.If it ________ break down within the first year，we would repair it at our expense.