`13.` How much do these book cost ?
`→` How much có 3 dạng viết lại :
`+` How much is/ are + S
`+` How much + do/does + S + cost ?
`+` What is the price of + S ?
`14.` We go to work by car everyday.
`→` drive = go ___ by car
`15.` I have never met her before.
`→` This is the first time + S + have/has + VPII
= S + have/has never + VPII + before
`16.` I haven't seen him for 2 days.
`→` Phủ định của hiện tại hoàn thành :
S + have/has not + VPII + for/since thời gian
`17.` They have worked in the garden for 30 minutes.
`→` S + have/has + VPII + for/since thời gian
`18.` I haven't phoned her since last Sunday.
`→` Phủ định của hiện tại hoàn thành :
S + have/has not + VPII + for/since thời gian
`19.` This is the fist time I have spoken to her.
`→` S + have/has never + VPII + before
= This is the first time + S + have/has + VPII ( lần đầu tiên làm việc nào đó )
`20.` We have become friends for 20 years.
`→` S + have/has + VPII + for/since thời gian
