A new hair-growing drug is being sold for three times the price, per milligram, as the drug's maker charges for another product with the same active ingredient.
A new hair-growing drug is being sold for three times the price, per milligram, as the drug’s maker charges for another product with the same active ingredient.
as
than
that
of what
at which
答案选的是D
但我觉得the price of what the drug's maker charges很罗嗦,因为what the drug's maker charges本来就是price啊