both的位置可以根据它的语法功能分为：
1 both of the pl 是一个名词性质的短语.作主语是在谓语之前,作宾语时在动词之后.如：Both of the writers were born in Chang an.He picked up both of the passegers from the airport.
of the pl 可以变为：of us/ them/you.也可以省略为：both
2 both (the) pl 中both相当于形容词,作定语,放在名词之前.如：both the brothers,both arms.
3 在名词或代词复数后作主语的同位语用,
1)没有助动词时,就放在谓语之前.如：They both work for the foreign company.The actresses both got into the lift.
2)有助动词时,通常就放在第一个助动词之后.如：They have both kept the secret.The managers are both in faour of the policy.
3)有助动词,但助动词后再没有其它词语时,就放在助动词之前.如：How silly you both are!Have they seen the movie?Yes,they both have.
4)作宾语的同位语时,放在宾语之后.如：I took photographs of them both.
4 both ...and ...是一个连词,用来连接并列的成分.如：She is both glad and sorry to see him.Both John and Jack were criticized by the boss.She was ashamed ,both for herself and for her sister.