"Greenhouse gases" in Para. 2 refer to ________________.
A: oxygen
B: hydrogen
C: carbon dioxide
D: air
A: oxygen
B: hydrogen
C: carbon dioxide
D: air
举一反三
- The synonym of CO2 is .（ ）。 A: hydrogen B: carbon monoxide C: carbon dioxide D: oxygen
- the gases which are responsible for causing the greenhouse effect, e.g. carbon dioxide
- ( ) is taken in by plants to make food. A: nitrogen B: hydrogen C: oxygen D: carbon dioxide
- The gas with maximum percentage in the atmosphere is ( ). A: nitrogen B: hydrogen C: oxygen D: carbon dioxide
- Greenhouse gases include . A: carbon dioxide B: CFCs C: methane D: nitrous oxide