A line of forts was built along the border to _________________________ (以防敌人进攻该国).
举一反三
- A new ( ) line will be built in the factory this year.
- The first telephone line was built in 1877.( )
- In the line "Imagine there's no countries", country refers to "border".( )
- Many new _____________ have been built along this road. A: houses B: rooms
- The first telephone line was built in 1877.（请用正确或者错误作答）