one做为代词的意思和用法

请先看一道题：

He is a hard-working student, _____ who will be successful in whatever career he chooses.

A. that B. he

C. one D. which

【分析】几个干扰项均有可能误选。此题答案选C，one 相当于 a student。类似地，以下各题也选one，它们分别相当于 a table, a break, a question, a Mexican carpet, a moment：

(1) A table made of steel costs more than _______ made of wood.

A. one B. it

C. those D. which

(2)“Why don't we take a little break?” “Didn't we just have _____?”

A. it B. that

C. one D. this

(3) The question is _____ of great importance.

A. that B. it

C. one D. what

(4) She wants a Mexican carpet, but she can't afford to buy ______.

A. one 　 B. it

C. them 　 D. the one

(5) Meeting my uncle after all these years was an unforgettable moment, _____ I will always treasure.

A. that B. one

C. it D. what