Here are the suggested answers for the sentences:

9. Youngsters love to eat from street **vendors** for the cheap price.
**Answer: B. vendors**

10. I wish we **could move** to a bigger house. I don’t have my own room.
**Answer: A. will move** (although "could move" is typically more correct in this context, it seems to fit best with the provided options)

11. I’ve just found 20 dollars in my pocket! **How cool!**
**Answer: A. How crazy** (as an expression of surprise here could be fitting)

12. "In the past, marriages used to be arranged by parents."
**Answer: B. That’s right. I suppose it was.**

13. We can see many **vendors** with two loads of fruits on their shoulders in the streets in Ha Noi.
**Answer: A. street vendors**

14. Mobile phones and computers are essential technological **facilities** for young generation.
**Answer: B. facilities**

15. The policeman is happy **finding** the kids safe and sound now.
**Answer: A. finding**

Feel free to ask if you need anything else!