—Do you regret paying 500 dollars for your necklace?

--No, I would gladly pay__________ for it.

A．two times as much

B．twice as many

C．twice as much

D．as twice as much

两产品重介质旋流器分选工艺主要应用于（）的原煤分选。

A.中煤含量较低

B.原煤可选性较好

C.精煤灰分较高

D.精煤灰分较低