`12`.Why did she go to the doctor ?

`->` Thì QKĐ ( NV ) : Did + S + V ? ( `12 - 14 , 21` )

`->` Why dùng để hỏi về lý do

`13`.What time did Nam leae home yesterday ?

`->` What time dùng để hỏi về giờ

`14`.What subject did he teach in the high school ?

`->` What subject dùng để hỏi về môn học

`15`.How was the homework yesterday ?

`->` Thì QKĐ ( ĐT Tobe - NV ) : Was / Were + S + adj / n ?

`->` How dùng để hỏi về cảm giác 

`=>` Was `+` He , She , It 

`16`.How many roses are there in the garden ?

`->` Thì HTĐ ( ĐT Tobe - NV ) : Is / Am / Are + S + adj / n ? ( `16 , 18 , 20` )

`=>` Are + You , They 

`-` How many + N đếm được : Dùng để hỏi về số lượng

`17`.Who will Liz send these letters to ?

`->` Thì TLĐ ( NV ) : Will + S + V ?

`->` Who dùng để hỏi về người

`18`.What is your favourite subject ?

`->` What dùng để hỏi về cái gì

`19`.How often do you go to the movie ?

`->` Thì HTĐ ( NV ) : Do / Does + S + V ?

`=>` Do + You , They

`->` How often dùng để hỏi về mức độ thường xuyên

`20`.Is he good at drawing ?

`=>` Is + He , She , It

`=>` Reply : Yes , S + is / am / are `-` No , S + isn't / 'm not / aren't

`21`.When did John go to Viet Nam ?

`->` When dùng để hỏi về mốc thời gian

`\text{# TF}`

12, Why did she go to the doctor ?

"Why"  được dùng để đặt câu hỏi với các từ lí do, nguyên nhân

13, What time did Nam leave home yesterday ?

"What time" cụm từ được dùng để hỏi giờ

14, What did he teach in the high school?

" What " : cái gì

15, How was the homework yesterday?

" How" : như thế nào

17, Who will Liz send these letters?

"Who" : ai

18, What is your favorite subject?

19, How often do you go to the movie?

" How often " : câu hỏi chỉ tần suất

20, Is he good at drawing?

21, When did john go to Viet Nam?

" When ": khi nào