2。3。3 句中有非限制性的词或短语之类，以逗号标出以示插入成份：
1。 Her husband， Bill， is a scientist。 (Bill 为插入成份)
2。 Kent Howard， my English teacher， is from America。 (插入成份 my English
teacher)
3。 Her father， who is a famous scholar， teaches English。(插入成份 who is a
famous scholar)
4。 Eleanor， his wife of thirty years， suddenly decided to open her own
2。3。4 句中的城市名如果和它的省、州、国名并列，省、州、国名前后须加逗号：
1。 We visited Hartford， Connecticut， last summer。 (Connecticut 为插入成份)
2。 Paris， France， is sometimes called "The City of Lights。" (France 为插入
成份)
3。 Hartford， Connecticut"s investment in the insurance industry is well
known。(Connecticut"s 为所有格式，后面不可加逗号喔)
2。3。5 句中带着连接词(but， and， or。。。)的插入成份的前面不可加上逗号：
1。 The Red Sox were leading the league at the end of May， but of
course， they always do well in the spring。 (but 的后面不可加逗号)
2。 The Tigers spent much of the season at the bottom of the league， and
even though they picked up several promising rookies， they expect to be
there again next year。 (and 的后面不可再加逗号)
2。3。6
向人说话时，逗号放在对方名字或称谓之后、之前或者前后都加：
1。
John， come here。 (John， 逗号在名字之后)
2。
Open the door， John。 ( ，John 逗号放在名字之前)
3。
It is， Sir， not my fault。
( ， Sir， 逗号放在称谓前面和后面)
2。4
替代句子里某个成份
2。4。1 用逗号替代句子里某部份，表示字词的省略：
1。 The lion is the symbol of courage; the lamb， of meekness。 (the lamb， of
meekness 原本应该是 the lamb is the symbol of meekness)
2。 George was the hard worker， John， the lazy one。 (John， the lazy one 原
本应该是 John was the lazy one)