1．one作代词时，代替上文提到的单数可数名词，以免引起重复，其复数形式是ones。其主要结构有：
1）a／an／the＋形容词＋one，如：an orange one
2）the ＋one ＋介词短语，如：the one in my pencilbox
3）this ／that one，如：
Here are two pens．This one is Jim's ，and that one is Tom's．
4）the ／some ＋形容词＋ones，如：some brown ones
2．“动词＋副词”短语（如put away ／on ／up，take off，know down等），后接人称代词作宾语时，其宾格应放在副词之前；若用名词作宾语，则可放在副词之前或之后。如：
Please put your football socks away．（＝Please put away your football socks．）请把你的足球袜放好。
3．pick up表示“拾起、捡起”。另外，它还有“得到、学会”、“驾车去接某人”、“恢复健康”、“继续（讲故事、谈话、友谊等）”意思。如：
I didn't quite understand how they got the books back so quickly until I picked up a book Grandma had left one day．直到有一天我捡到祖母丢失的一本书我才明白他们怎样如此迅速地得到书。
He picked up French while he was staying in Paris．他在巴黎时学会了法语。
Pick me up at the hotel．到宾馆接我。
She picked up soon after the operation．她手术后恢复很快。
We can pick up the story where we stopped yesterday．我们继续讲我们昨天没讲完的故事吧！
