Viết lại câu: Do you enjoy flying to Ho Chi Minh; Did it take him twenty minutes to solve this problem?

21. Do you enjoy flying to Ho Chi Minh
=>Are
22. Did it take him twenty minutes to solve this problem?
=> Did he
23. It is one year since we last met together in our wedding
=>We
=> The last time
24. Is this the first time have you chose a bad bicycle?
=>Have you
25. How long have you studied English?
When