－There is a lot of smoke coming out of the teaching-building there．

－Really?It ________ be a fire, most probably．

A．can

B．ought to

C．have to

D．must

When winter comes, ________ spring be far behind?

A．must

B．should

C．will

D．can

The weather in the south is generally warm, but it ________ be very cold sometimes．

A．must

B．can

C．should

D．ought to

It is sleeping late in the morning that ________ late for work．

A．lead to being

B．contribute to being

C．leads to be

D．contributes to being

Eating too much fat can ________ heart disease and cause high blood pressure．

A．contribute to

B．attribute to

C．attend to

D．devote to

I was told that there would be 50 teachers ________ the meeting．Will you attend it?

A．attend

B．to attend

C．attending

D．attended

With online course Crazy English has over 20 million students all over China ________ the class through Internet．

A．attend

B．attended

C．attending

D．to be attending

－Will you go and attend her party?

－No, ________．

A．even though invited to

B．even if inviting

C．if not invited

D．unless being invited to go

Jack is making up his mind to get a ticket for the concert ________ it means standing in a queue all night．

A．as if

B．even if

C．in case

D．as long as

Since you have made such good preparations, there ________ be any problem about passing the coming exam．

A．mustn’t

B．shan’t

C．shouldn’t

D．needn’t