Particulates may also be classified by their origin: .
A: Primary—emitted directly from a process
B: Secondary—subsequently formed as a result of a chemical reaction
C: Smoke and fly ash from forest fires
D: Pollens and other aeroallergens
A: Primary—emitted directly from a process
B: Secondary—subsequently formed as a result of a chemical reaction
C: Smoke and fly ash from forest fires
D: Pollens and other aeroallergens
A,B
举一反三
- In the fusion reaction of elements formed in the universe, carbon nuclei can be directly generated from helium nuclei. A: 正确 B: 错误
- The 12 years of primary and secondary schooling may also be completed outside the USA.( )
- Which of the following is NOT true? A: Acid rain also damages buildings and railway railings. B: Acid rain kills plants and water animals but is not really harmful to humans. C: Acid rain may attack the regions where it is formed and other regions as well. D: Smoke from factories and power-stations in the USA is the main cause of acid rain in Canada.
- People fly to other places from there.
- Why was an airport forced to close down A: Because the blazes from the fires were too hot. B: Because the smoke from the fires were too thick. C: Because it was too droughty at the airport. D: Because it rained heavily there.
内容
- 0
Environmentalists are concerned about loss of ______ that will result from destruction of the forest in the Amazon.
- 1
The fruit delivered directly from the orchard was __________ also delicious.
- 2
In the market research phase, research is either primary or secondary research, which of the following ones are primary research data? A: Data collected from surveys B: Data collected from feedback C: Data collected from library D: Data collected from journal
- 3
Diachronic study of word meanings is concerned with how a word develops its ______ meaning from its _____ meaning. ( ) A: primary; derived B: derived; primary C: central; secondary D: secondary; central
- 4
The reaction to culture shock may differ greatly from person to person.