Choose the word whose underlined part is pronounced differently

Ex1. Choose the word whose underlined part is pronounced differently.
1. A. school B. chemist C. machine D. ache
2. A. hard B. who C. honest D. house
3. A. passed B. danced C. lived D. walked

Ex2. Choose the word A, B, C or D whose main stress is different from the others in
the group.
1. A. translation B. difficult C. unluckily D. agree
2. A. Vietnamese B. engineer C. celebration D. product