3.
1They are going to visit Da Nang and stay at a hotel
2I'm going to stay there for a week
3Do you want to travel to Ha Noi this week?
4Lan and Hoa are going on vacation this summer
5Who are you going to be with during the summer vacation?
6Our hotel is next to a beautiful park
7Sa is going to stay at his friend's house in Nha Trang for three days
8Their uncle's house is by the beach

13.D
14.C
15.A
16.D
17.C
18. C
19.D
20. D
bài 3: 
1. in
2. for 
3. by 
4. on 
5. with
6. to
7. at
8.  from
 

3A4A5C6C7D8A9C10B.....