It now appears that they also have an important influence on the geophysical processes that propel the plates across the globe.

现在看来，它们还对推动板块在地球表面漂移这个地球物理学过程有着重要影响。

【分析】红色部分应包括连词that 在内，那么，that they also have an important influence on the geophysical processes that propel the plates across the globe，是appears 的表语从句。It 也不是形式主语，而是一个虚拟的主语。

道理很简单：如果把that 从句分析为appears 的主语从句，那么appears 缺少表语，句子不完整。

那么，这个it 是什么呢？我认为：

英语中的it，用于某些句式中，用法相当特殊，一是词性不明，二是词义不清。它究竟指代什么，很难找出确切的答案。除了叫“虚拟主语”（ dummy subject），还叫“假主语”（sham subject），“不定主语”（indefinite subject），也有人称之为“无确切含义的it”（unspecified it）。有一点是肯定的：it 的语法意义在于，它弥补了句子成分的空缺而让句子完整。

appears 是系动词，属于“感官类”。它的表语从句，除了用that 引导外，还可以可以由as if, as though, like 引导。从这一点就可以看出，除了that 引导的从句以外，后面的从句也都是“表语从句”，通过类比，即可导出结果。

例如：

It appears that they also have an important influence on the geophysical processes that propel the plates across the globe.

It appears as if they also have an important influence on the geophysical processes that propel the plates across the globe.

It appears as though they also have an important influence on the geophysical processes that propel the plates across the globe.

It appears like they also have an important influence on the geophysical processes that propel the plates across the globe.

除了appear 以外，seem 也具有同样的用法。

It seems that they also have an important influence on the geophysical processes that propel the plates across the globe.

It seems as if they also have an important influence on the geophysical processes that propel the plates across the globe.

It seems as though they also have an important influence on the geophysical processes that propel the plates across the globe.

It seems like they also have an important influence on the geophysical processes that propel the plates across the globe.