-（）？A lot of things are on sale.—That’s a good idea.Let’s go.

单项选择题-we need some toilet paper.-（）.

A.let’s go to the bookstore
B.let’s go
C.let’s buy them
D.let’s get some 

单项选择题Polly enjoys ( )in a band in her free time.play the guitarB. to playing the guitarC. playing the guitar

单项选择题What causes cavitation in a centrifugal pump （）．

A.Vapor
B.Rough
C.Worn
D.Heavy

单项选择题l need some red ink badly，butthere’s （）at hand.

A.nothing
B.a little
C.not
D.none

单项选择题If I（）his email address，I would have sent him a message yesterday.

A.have known
B.had known
C.will know
D.know

单项选择题He read my credit card number out loud in front of customers （）I could stop him.

A.before
B.while
C.as
D.since

单项选择题-I’m afraid I have to say goodbye to you.-（）.

A.I’m sorry
B.That’s all right
C.Never mind
D.Good night

单项选择题this is the man（）last night.

A.whom I saw him
B.who I saw
C.which I saw
D.who I saw him

单项选择题（）you will cook the dinner，I will do the washing-up afterwards.

A.If
B.Unless
C.When
D.While

单项选择题James decided not to go out （）he was still really tired.

A.whether
B.because
C.although
D.as