Just then we heard a horse outside, and there was a light knock on the door.

就在此时我们听到外面传来马声，然后是轻轻的敲门声。

There was a light knocking at the door.

门外传来轻敲声。

Because, both the wave theory and the particle theory of light predict that light knocks electrons out of the metal.

因为，波理论和粒子理论都假设光会排斥板中的电子。

He hadn't moved or spoken a couple of minutes later when there was a light knock at the door and Candy came in wheeling a tea wagon, with a crisp white cloth, silver-covered dishes, a pot of coffee, and two bottles of beer.

几分钟后，当轻轻敲门声时，他没有动，也没有说话，坎迪推着一辆茶车走了进来，车上有干净的白布、银盘子、一壶咖啡和两瓶啤酒。啤酒。