在 It's obvious that...（……是显然的）这种句型中，that 引导的是主语从句，做真正主语，it 做形式主语。如：

It was obvious that Gina was lying. 吉娜显然是在撒谎。

It was immediately obvious that the bag was too heavy. 马上就发觉这个包太重了。

It’s obvious that there’s a very real chemistry between them. 很明显他们俩是真的来电了。

It was obvious that she had done her homework and thoroughly prepared for her interview.  很明显她为面试做足了功课，准备很充分。

From his angry reply it was obvious that I had touched a sensitive spot. 从他回答时怒气冲冲可以看出，很明显我触到了他的痛处。