Only after reaching eighteen       join the army.

A. have you; you can     B. have you; can you      C. you have; you can     D. you have; can you

The students       on the professor’s lecture now and then.

A. took note           B. took notes                C. took notice                D. took action

The town’s drinking-water _____ with prim chemicals at present.

A. contaminates     B. is contaminated     C. is being contaminated    D. has been contaminated

 I feel that it was time for me to ____.

A. take actions          B. take an action          C. take the action       D. take action

They        their side of the field very well.

A. defended           B. protected                 C. keep                    D. prevent

Her father gave her the ___ of going on to college or starting to work.

A. chance             B. opportunity                C. alternative             D. possibility

He soon found himself       his new co-workers.

A. in harmony of        B. in the harmony of       C. in harmony with     D. in the harmony with

      is a good chance that I'I1 finish the work tomorrow.

A. It                 B. There                     C. This                    D. That

Access        the mountain-town is often difficult because of the bad roads.

A. of                 B. with                     C. to                      D. on

 Once out of the earth’s gravity, the astronaut is        by the problem of weightlessness.

A. affected                    B. effected                   C. related                 D. offered