如果原句用 have lost,意思就变了,就变成：我开不了门,因为我丢过钥匙,但现在已经找到的.有一种现在完成时表示现在之前业已完成的动作,虽然其效果或影响仍然存在但已不再继续,例如：Thomas has studied Russian.(现在不再学俄语)
I have lost the key(说明现在已找到）
影响还在,但动作已经停止了.
可能你会问：he has died不就说明他现在又火锅来了吗?所以he has died 后面必须接时间段,就是for xxxyears.
再把你上面的例子修改一下：I havn't eaten for three days,for I have lost the key to the door for three days.