a/ Minh goes to the karate club( three times a week. )
  $\text{→  How often does Minh go to the karate club ?}$

Giải thích : three times a week => ta sử dụng How often . 
b/ They go to school (by bike). 

$\text{  → How do they go to school ?}$

Giải thích : by bike ( hỏi phương tiện ta sử dụng how + do/does + S+ V ? )
c/ Tuan went to the cinema with( hís friends. )
$\text{ →  Who did Tuan go to the cinema with ?}$

Giải thích : ai đó , danh từ sử dụng từ để hỏi là Who 
d/ It is (about 5 km) from the post office to the bank.
$\text{→How far is it from the post office to the bank ?}$

Giải thích : Hỏi quãng đường ta sử dụng : How far + tobe + S + from + ( địa điểm ) + to ( địa Điểm 2)
e/ Jane is waiting for (the bus) at present. 

$\text{→ What is the Jame waiting for at the present ?}$

Giải thích : the bus sử dụng từ để hỏi what 
f/ I was late for class this morning (because I stayed up late last night. )
$\text{→ Why did you late for class this morining ?}$

Giải thích : because +...... (lý do ) Sd từ để hỏi " why "
g/ She bought these clothes (in the supermarket. )

$\text{→ Where did she buy these clothes ?}$

Giải thích : In the supermarket ( địa điểm ) => sd : where 
h/ He is (practicing the piano) in the music room. 
$\text{→ What is he doing in the music zoom ?}$

Giải thích : practicing the piano ( đang làm j ở thời gian  này ) => sd : What + tobe + S + V-ing + O?

a/ How often does Minh go to the karate club? 

(How often: hỏi cho mức độ, tần suất, số lần

Eg: I go to school every day.

=> How often do you go to school?)

b/ How do they go to school?

=> Họ đi đến trường như thế nào?

Họ đi đến trường bằng xe đạp

c/ Who did Tuan go to the cinema with?

=>Tuan went to the cinema with( his friends. )

His friends -> Who

d/ How far is it from the post office to the bank?

=> about 5 km -> How far: nói về khoảng cách

e/ What is Jane waiting for at present?

=> Jane is waiting for (the bus) at present.

What -> the bus

f/ Why did you late for class this morning?

=> I was late for class this morning because I stayed up late last night. 

Why->because I stayed up late last night.

g/ Where did she buy these clothes?

=> She bought these clothes in the supermarket.

in the supermarket-> where

h/ What is he doing now?

=> He is practicing the piano in the music room.

what is he doing->He is practicing the piano