热虹吸式重沸器的特点是（）
A.汽化率高
B.本身具有蒸汽空间
C.加热段停留时间长
D.出塔产品缓冲容积大
参考答案：D
Katy and Sandy live in __________ town, and they both get __________ e-mail a day.[ ]
A. /; an
B. the; an
C. the; a
D. /; the
受电弓滑板在工作高度范围内对接触网导线的压力称为受电弓的动态接触压力。
d Sandy live in __________ town, and they both get __________ e-mail a day.[ ]