I. 
1/ My brother can repair the bike himself.
2/ They have a great time. They really enjoy themselves.
3/ Don’t worry about us. We can look after ourselves.
4/ This exercise isn’t difficult. Do it yourselves.
5/ She cut herself.
6/ I made this shirt myself.

II. 
1. Hoa went to school late this morning because her bike broke down.
⇒ Why did Hoa go to school late this morning?
2. I have to tidy the living room everyday.
⇒ What do you have to do everyday?
3. She’ll be home after dinner
⇒ When will she be home?
4. Lan used to live on the farm when she was young.
⇒ Where did Lan use to live when she was young?
5. My mother gave me a new bike on my 14th birthday.
⇒ What did your mother give you on your 14th birthday?
6. Nam often walks to school.
⇒ How does Nam go to school?
7. I need to improve Math and English.
⇒ What subjects do you need to improve?
8. Nga studied well this semester.
⇒ How did Nga study this semester?
9. We have studied English for 4 years.
⇒ How long have you studied English?
10. My best friend is very helpful and friendly.
⇒ How is your best friend like?