It is compulsory for the tourists to learn about the vital eco-systems before arriving.

A. Tourists are free to learn about the vital eco-systems before arriving.

B. It is optional for tourists to learn about the vital eco-systems before arriving.

C. Tourists are not required to learn about the vital eco-systems before arriving.

D. Tourists are required to learn about the vital eco-systems before arriving.

Bài tập Trắc nghiệm Tiếng Anh 10 - Unit 10: Ecotourism (Writing)