上述关系代词who，whom，which和that若在定语从句中作宾语，往往可以省略。例如：
a. Tina likes the present which I gave her for her birthday.
b. Tina likes the present that I gave her for her birthday.
c. Tina likes the present I gave her for her birthday.
d. I like the people who I work with.
e. I like the people I work with.
f.I’m talking about friends who you can share almost everything with.
g. I’m talking about friends you can share almost everything with.