阿摩線上測驗
22. Fine particulate matter (PM2.5) is an air ________ that affects people's health such as causing or aggravating respiratory and heart disease.
(A) pollutant
(B) substance
(C) pollution
(D) objector
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統計： A(84), B(38), C(171), D(8), E(0) #2310659
統計： A(84), B(38), C(171), D(8), E(0) #2310659
