Свопросами.
1) the armchair is very comfortable.
(задать вопросы: общий, разделит, отрицание, what)
2)we are having an english lesdon.
(задать вопросы: общий, разделит, отрицание, what)
3) alice wears a uniform in class.
(задать вопросы: общий, разделит, отрицание, where)

1.общий-Is the armchair very comfortable?разделит-The armchair is very comfortable,isn’t it?отриц-The armchair isn’t very comfortable.What-What is very comfortable
2.общий-Are we having an English lesson?Раздел-we are having an English lesson,aren’t we?отриц-we aren’t having an English lesson.What-What lesson are we having?
3.общ-Does Alice wear an uniform in class?раздел-Alice wears an uniform in class,doesn’t she?отриц-Alice doesn’t wear an uniform in class.Where-Where does Alice wear an uniform?