The engineers in this lab spent several weeks _______their plans for the new bicycle.

Many kinds of animals are believed to have _________from the earth

The _______ work continued for more than a week but there was still no sign of the missing boy.

He _______ to study harder in the future so that he could have more opportunities to find a better job.

He tried to _____ __relations with his former wife but he failed.

Much of the news provided by this newspaper is_______, not foreign.

The doctors _______ the medicines to the people in the flood area.

We are _______ at the rapid progress Mark has made in this semester.

She is already 16years old. But she _______as if she were still a little girl.

This river forms a natural _______ between China and Korea.