17

B.of ⇒ with

Vì agree đi với giới từ with

18

C.can ⇒Could

Vì có some years ago nên phải dùng ở dạng quá khứ

Ex 6: 

Carrying your own bags is such a chore. With Gita Bot, worry no more. This compact robot is designed to follow you around 19.D.while you're out and about in town or on the way to work.The bot is capable 20.C.of carrying the equivalent of a case of wine, a loaded rucksack or two shopping bags, so it's an 21.A.ideal companion for a quick trip down to the shops. In the future, you'll be able to leave the car at home and stretch your legs without the misery of carrying your 22.B.shopping home. 

Exercise 5

17,B.of ⇒ with

18,C.can ⇒Could

Exercise 6 

19,D

20,C

21,A

 22,B

:)