Jack came home very late and knocked at the door for nearly ten minutes___his wife opened it.A.when B.before C.until D.as 为什么选before而不选until,这是华师一附中09年的招生题,

Jack came home very late and knocked at the door for nearly ten minutes___his wife opened it.
A.when B.before C.until D.as 为什么选before而不选until,这是华师一附中09年的招生题,