1.+of door, house, car, bag钥匙
He locked the bag and put the key in his pocket.他锁好了包并把钥匙放进了口袋。
Where are my car keys?我的车钥匙在哪里？
2.+of valve, clock钥匙；扳手
3.the key to sth
+ victory, mystery…的关键(或诀窍)
The key to our victory was the fact we believed in ourselves.我们取得胜利的关键是自信。
A new witness may provide the key to the mystery.一个新的目击者也许能提供解开谜团的关键线索。
4.+of computer, mobile phone按键；+of piano, keyboard键
She ran her fingers lightly over the piano keys.她的手指轻巧地划过钢琴琴键。
Press the hash key now.现在按下井号健。