What does the professor mean when he says this
A: Little is known about defining a substance as an air pollutant.
B: The substance isn’t an air pollutant when there is a very little in the air.
C: The substance can’t be judged to be an air pollutant only from its actual concentration level.
D: The actual concentration level means little to peopl
A: Little is known about defining a substance as an air pollutant.
B: The substance isn’t an air pollutant when there is a very little in the air.
C: The substance can’t be judged to be an air pollutant only from its actual concentration level.
D: The actual concentration level means little to peopl
举一反三
- The water (or snow) can become acidified when a pollutant combines with______ in the air.
- What is the talk mainly about A: The definition of air pollutant. B: The causes of air pollution. C: The dangers of air pollutants. D: Ways to fight air pollution.
- There is little air on ______ moon. A: [A] the B: a C: /
- 智慧职教: 3.S1:Isn't the emergency air compressor started? S2:Yes. But the emergency air compressor can't supply enough starting air to the air receiver for the auxiliary engine. Q:How is the emergency air compressor?
- The doctor said that there was only a slim hope of survival for the people in the air crash. A: numerous B: considerable C: moderate D: very little