The government sent out some experts to determine just what ________ the explosion．

A．caused        B．was causing        C．has caused         D．had caused

Some projects were purposely organized to help the students learn to share things and  ________ each other.

A．stick to              B．attach to             C．relate to             D．differ from

—Tom was caught stealing in a supermarket．

—It ________ be true! He is above that sort of things．

A．mustn't             B．can't           C．may not                 D．shouldn't

—I didn't see Tom in the party．

—He was ill，________ he didn't come. 

A．in case             B．as if          C．now that         D．so that

On his first day working as the new manager，he lost no ________ in organizing his office.

A．patience            B．effort          C．time          D．chance

Though I haven’t seen him for a long time，I still remember ________ he was quite a short boy．

A．when             B．where             C．how                D．why

I know the course is hard but I am quite determined to ________ it through.

A．stick          B．see           C．check               D．try

The sudden quake left half the villagers ________ under their destroyed houses.

A．buried         B．to be buried           C． being buried          D． burying

Can you imagine ________ it was that drove him into such poverty?

A．what              B．how                C．why              D．when

He claimed that the company had tricked him into doing what he would not have done _____．

A．otherwise           B．however           C．forever            D．therefore