Đề thi học kì 2 THPT Lương Ngọc Quyến môn Anh lớp 11 năm 2021
Question 26. In one well-known city, traffic policemen have to wear oxygen masks _____.
A. in order to protect themselves from being injured
B. because there are so many cars on the streets
C. in spite of poisonous gases
D. because of air pollution
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Theo TTHN