问题补充：
How much more expensive do you think a flat in a downtown area is than in a suburban area?
A. one
B. the one
C. that
D. those
答案：
(答案→)A. one
B. the one
C. that
D. those
解析：句意：你认为在市区的公寓比在郊区的公寓贵多少？这里用one代替flat不是特指是泛指，one可代替同类的可数名词的单数，one与that则指代同名异物。但one为泛指, 相当于a/an＋名词; that为特指, 相当于the ＋名词。所以one所指代的名词的修饰语一般为 a/an /some /any; that所指代的名词的修饰语往往是the /this /that。that既可以代替不可数名词也可以代替可数名词单数, 代替可数名词复数时用 those。 one既可代替事物, 也可代替人, that只能代替事物而不能代替人。有时可以用the one或the ones代替that或those。 one一般有前置修饰语, 有时也可有后置修饰语或不用修饰语。而 that不能有前置修饰语, 但可有后置修饰语。故选A。
