Translation of "Tear" in Chinese

I saw my sister tear up the letter.

我看到我的姊姊把信撕了。

They will tear down the old building in two days.

他們將在兩天內拆除這棟舊的建築物。

To those who would tear the world down: we will defeat you.

那些想要颠覆这个世界的人们，我们将击败你们。

My tear glands have been loose all my life, but once I passed 40 I became much more easily moved to tears.

曾经泪腺比较发达，过了40之后就没那么灵敏了。