In the world today, advertising helps sell more things to more people. This in turn makes it possible to produce more things to sell. At some times it even helps make things cost less. Radios, for example, _____ much more than they do today because they were turned out slowly and expensively by hand.
選項: (A)used to cost (B) will cost (C)cost (D)were used to cost
他的答案給的是(A)
他的解釋寫的是 表示過去習慣: (1)used to + V.
(2)was /were used to + Ving
(3)簡單過去式