电弧焊时,经常发生电极和焊件的短路现象,所以应限制其短路电流不能太大,通常短路电流应小于工作电流的()
A.1.5倍
B.1.8倍
C.2倍
D.2.5倍
参考答案:C
The explorers failed to find the cave because it was not located they had expected it to be.
A.which
B.that
C.where
D.what
下列各项,可在使用有效抗结核药物的同时,加用糖皮质激素的是
A.伴咯血
B.空洞形成
C.急性粟粒型肺结核
D.干性胸膜炎
E.抗痨药引起肝损伤