The number of rare animals are decreasing so rapidly that they are in danger of becoming extinct.

 A. Mr. Forest admitted making a mistake in the calculations.

 B. Mr. Forest admitted having made a mistake in the calculations.

 C. Mr. Forest admitted to having made a mistake in the calculations.

 D. Mr. Forest admitted to have been made a mistake in the calculations.

 A. I was introduced to a man who brother I had seen on TV the evening before.

 B. I was introduced to a man which brother I had seen on TV the evening before.

 C. I was introduced to a man that brother I had seen on TV the evening before.

 D. I was introduced to a man whose brother I had seen on TV the evening before.

 A. for

 B. in

 C. on

 D. with

 A. different

 B. differ

 C. differently

 D. difference

 A. children whom

 B. children

 C. children who

 D. whose children

 A. happy

 B. dirty

 C. energy

 D. supply