此題考查it與one的區別

請看下面一道題：

I want very much to buy a colour TV set, but I can’t afford _________.

A. it                        B. one                        C. this                        D. that

答案選B，但容易誤選A。it 和 one 的區別可簡單地概括為：it = the + 名詞，one = a + 名詞。如：

I haven’t any dictionaries, and I want to borrow one. 我沒有詞典，我想借一本。(one = a dictionary)

I have two dictionaries, and I can lend one to you. 我有兩本詞典，我可以借一本給你。(one = a dictionary)

I have a dictionary, and I can lend it to you. 我有一本詞典，我可以把它借給你。(it = the dictionary)

根據上面一題的語境，句子后半截顯然應該是 … but I can’t afford a colour TV set，而不是 but I can’t afford the colour TV set，所以答案選B。