保存断肢的适宜温度为()
A.-8℃
B.-4℃
C.0℃
D.4℃
E.8℃
参考答案:D
We were talking and laughing, when our teacher came in and asked us what all the ______ was about.
A.excite
B.exciting
C.excited
D.excitement
在金属表面上形成能抑制金属溶解过程的电子导体膜,而这层膜本身在介质中的溶解速度又很小,以致它能使金属的阳极溶解速度保持在很小的数值上,则这层表面膜称为()
A.预膜
B.钝化膜