`7`. It was really interesting in learning classical music for many students.

`-` be interesting in: Ving/ st: thích thú làm gì/ cái gì ( interest cũng có thể có đuôi "ed" nhưng vì chủ ngữ của câu này chỉ sự vật, sự việc nên phải dùng adj đuôi "ing").

`8`. It is difficult for her to practice writing every day.

`-` be+ difficult+ for+ sb+ toV: khó khăn với ai để làm gì

`9`. Remember to turn off the lights before going out!

`-` Don't forget+ toV= Remember+ to V

`10`. Don't forget to lock the door before leaving

`-`  Don't forget+ toV= Remember+ to V

`11`. Remember not to stay up late at night.

`-` remember (not)+ to V: nhớ ( không)phải làm gì

`12`. We ought not to eat too much before going to bed.

`-` should+ not +V= ought+ not+ toV: không nên làm gì

`13`. She ought not to take aspirins because the doctor didn't say that.

`-` ought not+ to V: không nên làm gì

`14`. You ought to brush your teeth carefully every day.

`-` ought+ to V: nên làm gì

`15`. Children ought not to spend too much time on video games.

`-` ought+ to V: nên làm gì

`16`. You ought to keep the house clean and tidy.

`-` ought+ to V: nên làm gì

`17`. It usually takes Mr. Johnson 15 minutes walk to work.

`-` take+ sb+ khoảng thời gian+ toV: Ai đó mất khoảng bao lâu để làm việc gì

`18`. It takes Mary two hours to study in the library every week.

`-` take+ sb+ khoảng thời gian+ toV: Ai đó mất khoảng bao lâu để làm việc gì

`19`. I often spend 10 minutes walking from my house to school. 

`-` spend+ st+ Ving: dành ra cái gì để làm gì

`20`. Does that work spend half an hour for you to do?

form:

it+take+o+time+toV : dành bao nhiêu thời gian làm gì 

S+spend + time +Ving :dành bao nhiêu thời gian làm gì 

1 .it usually takes 15 minutes to walk

2. it takes 2 hours to study in the library every week 

3. i often spend 10 minitues walking my house to school 

4. does it take half an hour to do that work ?