Mark the letter A, B, C, or D to indicate the correct answer to each of the following questions.

Câu hỏi

The medical authorities warned everyone not to drink the water without _______it.

A. being boiled

B. boiling

C. having boiled

D. having to boil

Đáp án
B. boiling

Câu hỏi thuộc Bài tập:

E11- GS- Unit 4- Practice 6