It is hard to say what kind of person he is．Sometimes he is very friendly; at other times he ___ be very cold．

—God！My cell phone is missing.—You ________ have left it at home.I heard you telephone our daughter in the bathroom.

I want        a book for my granddaughter Linda who is 2 years old.

I like playing        basketball and playing        erhu. 

So many people violate traffic regulations that we ____ put too much emphasis on the importance of traffic safety.