3. join, take part in
[误]　He joined the League for two years.
[正]　He joined the League two years ago.
[正]　He has been in the League for two years.
[正]　He has been a League member for two years.
join指“参加”组织，成为一个成员，join sb.意思是“加入某人”，如指“参加……多长时间”就要用延续动词be in或be a ... member，而不能用join。
take part in指参加活动特别是大的运动。
 4. borrow, lend, keep
[误]　She has lent me the book for a week.
[正]　She lent me the book a week ago.
[正]　It's a week since she lent me the book.
borrow/lend是短暂性动词，在肯定句里不和表示一段时间的状语连用；
keep是延续性动词，可与表示一段时间的状语连用；
borrow意思是“借(进)”，后面跟介词from；
lend意思是“借(出)”，后面跟介词to，lend也可用于某些成语中，如lend sb. a hand。
 5. lie, lay, lain
[误]　She laid down the book and laid in bed.
[正]　She laid down the book and lay in bed.
lie有两个意思，一个是“说谎”，过去式和过去分词是在词尾加­d；另一个是“躺，卧；位于”，是不规则动词，其过去式和过去分词是lay、lain，现在分词是lying。lay意思是“放；孵(蛋)”，其过去式和过去分词是laid、laid。