She sent me a _______ letter thanking me for my invitation.

Smoke, dirt and noise are all kinds of ___.

Choose a suitable word or phrase (marked A, B, C, or D) to fill in each blank.

He has been very interested in doing research on _______ since he was at high school.

Are you sure that boys are more _______ than girls?

My mother used to be a woman of great _______, but now she gets old and looks pale.

He is not really friendly and makes no attempt to be _______.

Only a few of the many species at risk of extinction actually make it to the lists and obtain legal ____.

As an _______, Mr. Pike is very worried about the increasing of juvenile delinquency.

The more _______ and positive you look, the better you will feel.

John cannot make a _______ to get married to Mary or stay single until he can afford a house and a car.

Advanced technology can last our _______.

My parents will have celebrated 30 years of _______ by next week.

They had a ______ dinner last night and she accepted his proposal of marriage.

Children who are isolated and lonely seem to have poor language and ________.

It was such a boring speech that I felt _________.