1. Years ago this politician did a clever, but immoral thing, which laid the foundation of his fortune.

　　A. unethical

　　B. unexpurgated

　　C.unimpeachable

　　D.improper

　　2. It is always praiseworthy to admit one's errors and rectify them without delay.

　　A. straighten

　　B. correct

　　C.justify

　　D.identify

　　3. This special task calls for common sense, imagination, intelligence and tact.

　　A. prudence

　　B. bravery

　　C.diplomacy

　　D.coolness

　　4. "Do I understand that it is not compulsory for us to attend?" Mr. Johnson asked.

　　A. advisable

　　B. obligatory

　　C.indiscreet

　　D.necessary