You use whose after certain words, especially verbs and adjectives, to introduce a clause where you talk about the person or thing that something belongs to or is associated with.
I wondered whose the coat was.
我思忖着那件大衣是谁的。
You use whose to refer to the person or thing that something belongs to or is associated with.
I'm wondering whose mother she is then.
我想知道她会是谁的母亲。
I can't remember whose idea it was.
我不记得这是谁的主意了。
You use whose at the beginning of a relative clause where you mention something that belongs to or is associated with the person or thing mentioned in the previous clause.
I saw a man shouting at a driver whose car was blocking the street.
我看见一个人冲着一个司机大喊,因为那个司机的车挡住了街道。
a speedboat, whose fifteen-strong crew claimed to belong to China's navy.
一艘快艇,其船员超过15人,声称自己属于中国海军。
You use whose in questions to ask about the person or thing that something belongs to or is associated with.
'Whose is this?'—'It's mine.'
“这是谁的?” “是我的。”
'It wasn't your fault, John.'—'Whose, then?'
“这并非你的错,约翰。” “那么,是谁的呢?”
Whose car were they in?
他们坐在谁的车里?
Whose daughter is she?
她是谁的女儿?