电子刻蚀加工主要是通过热效应对工件进行加工,而离子刻蚀加工主要是通过()效应对工件进行加工。
A.撞击
B.溅射
C.注入
D.撞击、溅射
参考答案:A
Mr. Wang _____ table tennis well, though he suffers from a waist pain and _____ it for a long time.
A.played; has not played
B.plays; had not played
C.plays; did not play
D.plays; has not played
下列现象与氢键有关的是:( )
①H2O的熔、沸点比VIA族其他元素氢化物的高 ②小分子的醇、羧酸可以和水以任意比互溶 ③冰的密度比液态水的密度小 ④NH3在水中的溶解度很大 ⑤邻羟基苯甲醛的熔、沸点比对羟基苯甲醛的低 ⑥水分子高温下也很稳定:
A.①②③④⑤⑥
B.①②③④⑤
C.①②③④
D.①②③