A)John! What do you do?
I am writing a letter,
b) Does he help you every week?
c) We ate your cake an hour ago.
d) Did your mum decorate the New year thee a week ago?
e) In a month my parents will send me to London.
f) She does not know me well. Для разнообразия поставил отрицание
g) Now I am doing my homework.
h) Do they walk in the park every Sunday? У тебя вопросит знак не стоит. Если без него, то это будет просто:
h) They walk in the park every Sunday.