根据汉语提示填词
【小题1】________（财富）has not brought them happiness.
【小题2】Jack ________（锁）the door and took the key with him.
【小题3】You can cross the road in ________（安全）when the policeman holds up his hand to stop the cars.
【小题4】It's our duty to ________（守卫）this bridge and not let the enemy pass.
【小题5】He ________（闭）his mouth and refused to say anything more.