Choose the word (A, B, C, D) whose main stress is placed differently from that of the other.
1. A. question B. action C. pollute D. nation
2. A. vacation B. friendly C. century D. million
3. A. picnic B. water C. amount D. plastic
4. A. finish B. revise C. prefer D. produce
5. A. dancer B. simple C. describe D. traffic
6. A. develop B. introduce C. discover D. prepare
1c
2a
3b
4d
5c
6a