1 Some schoolgirls don"t wear uniforms
+ Some schoolgirls wear uniforms.
? Do some schoolgirls wear uniforms.
2 Does she cut her husband's hair?
+ She cuts her husband's hair
- She doesn't cut her husband's hair.
3 She does her homework everyday.
+ She doesn't do her homework everyday.
? Does she do her homework everyday.
* Chuyển sang câu phủ định ( thêm "not" vào trợ động từ )
* Chuyển sang câu nghi vấn ( đưa trợ động từ lên đầu câu )