在下列句子中 how 用作连词，引导一个名词从句，相当于 that ：

    She told us how she had to work hard. 她告诉我们，她不得不努力工作。/ He knows how you are a valued employee. 他知道你是位受器重的雇员。/ It's amazing how they completed the bridge so quickly. 他们如此迅速地建成了这座桥，真令人吃惊。（摘自《韦氏高阶英汉双解词典》p.1032）

    在第一个句子中，划线部分是宾语从句，作 told 的直接宾语；在第二个句子中，划线部分是宾语从句，作 knows 的宾语；在第三个句子中，划线部分是主语从句，作真正的主语，It 是形式主语。

    网友的句子与第三个句子结构相同：It's so beautiful how the water reflects the sky.

It's so beautiful how the water reflects the sky.

本句，how the water reflects the sky 是主语从句。

how 等于 that 或 the way。可以代入句中替换。

又如，以下3句意思相同：

It was boring how he kept complaining to his wife.

It was boring that he kept complaining to his wife.

It was boring the way he kept complaining to his wife.

实际上，三个红色单词引导的句子，都暗含着“方式”的意思。

how 引导名词性从句，有两个用法：

1. 表示疑问含义 “怎样”：

It is still a question how we should do the job.

2. 表示做事的方式 “如此这般，这样地”：

即网友的句子。