what has happened?I __ (lose) my key and can't open the door

问题描述:

what has happened?I __ (lose) my key and can't open the door

横线处填入 lost即可.
问句虽然是现在完成时,但是根据语境理解应该是追问刚才发生了什么,
回答直接用过去式就好,而且丢了钥匙这一行为是短暂的,也不必强调已经丢了,也就是说不必要使用现在完成时.