通常所说的煤气中毒就是CO中毒，有害气体主要通过（）和（）人体。
参考答案：呼吸道、消化道；皮肤侵入
—What do you think of the good news?
—Wonderful! It makes us _____．Most of us were _____about it
A．excited; excited
B．exciting; exciting
C．excited; exciting
D．exciting; excited
人口密度、年龄结构属于下列哪种宏观环境因素？
A．社会文化环境
B．政治法律环境
C．经济环境
D．科技环境
