金属-烤瓷熔合冠桥的后焊接常采用
A．汽油吹管火焰焊接法B．锡焊法C．烤瓷炉内焊接法D．激光焊接法E．点焊
参考答案：C
___ comfortably in his armchair, the old man enjoyed the light music over the radio with his eyes
half ___ . [ ]
A. Seating ; closed
B. Seated ; closed
C. Sitting ; close
D. Sat ; closing
一般要求船舶海水淡化装置所产淡水含盐量应低于（）mg/L（Cl-）。
A．1000
B．10
C．50
D．100
