1. There was a knock at the window.
    有人敲了一下窗户，

2. He started to complain about this wicked world but was interrupted by a knock at the door.
    他开始抱怨起这个邪恶的世道来，却被一阵敲门声打断了。

3. Did I hear a knock at the door?
    是有人敲门吗?

4. An illness which at twelve would knock us over, at eighty can knock us out, and into our grave.
    能使我们在12岁时病倒的疾病，到了80岁可能会使我们一蹶不振而进入坟墓。

5. At any moment he expected to hear the creature, feel it knock him to the ground, smell its breath — meet death.
    每时每刻他都感到将会听到那只动物的声音，感觉到它将他扑倒在地，闻到它的呼吸——面临死亡。

6. Just as Mrs. Richards was entering the dining room, there was a knock on the front door.
    理查兹夫人刚刚走进餐厅，前门就传来敲门声。

7. (There is a knock at the door.)
    （敲门声）

8. One evening little Hans was sitting near the fire when he heard a loud knock at the door.
    一天夜里，小汉斯正坐在火炉旁取暖，这时他听到有人在大声敲门。

9. I´ll knock again, Helen.
    海伦，我再敲一次。