熔化极气体保护焊，焊接工艺参数调节方式有一元化调节、两元化调节和（）。

A.多元化调节

B.抽头式调节

C.电压自调节

D.电流的自调节

Chomsky has made the distinction between linguistic competence and______.

A．linguistic performance

B．communicative competence

C．reading performance

D．universal grammar