英语语法分析

There is much comparability between pearl and nacre in shells.

珍珠与贝壳珍珠层具有较多的相似性，但也存在很多不同。

As a resul t, nacre thickness is sometimes just a cosmetic layer t hat can wear thin over time.

所以真珠质的厚度就像脸上化妆品，不久就会磨薄了。

Covered by her nacre tears, the grain of sand could not hurt her anymore: it had become smooth and harmless.

那粒沙子被她珍珠质的泪水包住了，再也不能碰伤她：它变得光滑，而且不再伤人。