搜题请搜索小程序“爱下问搜题”
问题 单项选择题

Halon gas will decompose and may form very hazardous toxic fumes when discharged（）.

A.directly on flames

B.at room temperature

C.in an extremely cold climate

D.None of the above

答案

参考答案：A

选择题

读“1991～2007年我国逐年排放SO2情况”图，我国SO2排放量居高不下，下列因素与此无关的是

A．能源消费结构特征

B．生产技术水平

C．环境保护观念

D．人口众多
查看答案
选择题

A giant helium(氦) balloon is telling residents of Paris how good or bad the air quality is. When it’s good, the balloon ----measuring 22 meters wide and 32 meters high---shines green. _________, it’s red.

A．Though terrible

B．Whenever good

C．If worse

D．When bad
查看答案