THE WORD THOSE IN PARAGRAPH 2 REFERS TO ____. A. BRONCHITIS AND AST...

6. - Tieng_anh_12-Giua_HK1_
Tiếng Anh Tieng_anh_12-Giua_HK1_

6. The word those in paragraph 2 refers to ____.

A. bronchitis and asthma B. carbon dioxide and nitrogen oxides

C. dangerous gases D. respiratory diseases