专题限时训练(六) [情态动词和虚拟语气]
(限时：10分钟)
( )1.—How much shall I pay for the phone call?
—You________. This is free of charge.
A．shouldn’t B．can’t
C．don’t have to D．mustn’t
( )2.—May I leave the office before 5 o’clock in the afternoon?
—No, I’m afraid you ________.
A．needn’t B. wouldn’t
C．mustn’t D．won’t
( )3.The outbreak of flu last year tells us that a sound public health system ________ be built up and strengthened in our country.
A．should B．can
C．will D．may
