________ that Tom got inside the room to see what was going on. [ ]

A. So strangely did he feel          

B. So strangely he felt

C. So strange did he feel            

D. So strange he felt

为保护焊工眼睛不受弧光伤害，焊接时必须使用镶有特制防护镜片的面罩，并按照（）的不同来选用不同型号的滤光镜片。

A.焊接材料

B.焊接电流

C.焊接速度

D.电弧长度