himself to supporting his brother’s son,he has to let one of his children leave school. [ ]

A.Having committed

B.Committed

C.Being committed

D.To commit

造成弧焊变压器焊机外壳带电的原因是（）。

A.焊机过载

B.焊接电缆过长

C.可动铁芯振动

D.未接地线或其接触不良