这些虫子太小了，你用肉眼看不到它们。

These bugs are so tiny you cannot see them with ___the ___naked ___eye.

在晴朗的夜晚，星星可以用肉眼看到。

Stars are visible to ___the ___naked ___eye on a clear night.

细菌通常太小，无法用肉眼观察。

Bacteria are usually too small to be observed with ___the ___naked ___eye.