Поставьте предложения в вопросительную и отрицательную формы. 1.our engineer will be busy tomorrow. 2.the classes are over at 4 o'clock. 3.your friend is fond of music. 4.they were absent yesterday.

В первом случае просто ставишь глагол на первое место
1. Will our engineer be busy tomorrow?
2. Are the classes over at 4 o'clock?
3. Is your friend fond of music?
4. Were they absent yesterday?
А во втором добавляешь к глаголу частичку not
1. Our engineer won't be busy tomorrow
2. The classes aren't over at 4 o'clock
3. Your friend isn't fond music
4. They weren't absent yesterday