They is never used adjectively, but always as a pronoun proper, and sometimes refers to persons without an antecedent expressed.
They had a baby last month
他们上个月添了一个宝宝
They had to call in a heart specialist
他们必须请心脏专门医生来
They operated on him last night
他们昨晚给他动过手术
they say
人们说, 据说, 通常认为
They say the film is an adventure story
他们说这片子是一个冒险故事
They serve good food in this restaurant
这家菜馆供应的菜很好
They signed off two hours ago
他们两小时以前就播完了
they'd
(=they had, they would)厚皮的
they'll
abbr. they will 他们将
they're
abbr. they are 他们是
they've
abbr. they have 他们曾经
they-all
[网络] 他们大家都;起身;他们都来帮助我了
theyself
[网络] 自己