問題詳情

【題組】17. What prevents toxic fumes from rising into the upper atmosphere?
(A) Smoke from factories.
(B) Polluted air from vehicles.
(C) Pollution levels in a city.
(D) Moisture in the air.

參考答案

答案：D
難度：非常困難0
統計：A(2),B(1),C(0),D(0),E(0)