Circle the correct form of use to

01 Đề bài:

A. Circle the correct form of 'use to'.

(Khoanh tròn dạng đúng của 'use to')

1. Long-distance travel use to / used to take longer than it takes today.

2. Why did travel use to / used to be so challenging in the past?

3. In the past, there didn't use to / used to be as many opportunities for trade as there are nowadays.

4. How did people use to / used to buy things before money existed?

5. Before trade with China began, people didn't use to / used to wear silk clothes.

02 Bài giải: