It is important that the boy （ ） an adult to take care of him.

Whenever we planned our vacations， mother could always offer some _____ suggestions.

I appreciate （ ） the opportunity to study abroad two years ago.

It is often _____ that human beings are naturally gifted to speak.

It is her beautiful eyes （ ） attract most of the fans.

Air pollution is obviously one of the major _____ of city life.

The first textbook（ ） for teaching English as a foreign language came out in the 16th century.

What time would it be convenient _____us to meet again?

After （ ） the numbers in every possible combination, we finally hit on a solution.

I told them I was perfectly _____ to help if they asked.

（ ） all her friends and money gone, Kate felt totally hopeless.

Not until that day _____ the importance of good manners in a job interview.