This proves (that) I was right.

这证明我是对的。

《牛津词典》

All this proves that cancer is complex.

所有这些都证明肿瘤是复杂的。

youdao

This proves that your program is working correctly.

这证明您的程序在正常工作。

youdao

Now, in answer to your question, " I think this proves that or I won't say "Proves."

再来回答你的问题，我认为这证明了，不该用“证明“

耶鲁公开课 - 公正课程节选

This proves to be really difficult in the real world because in the real world it's hard to pull apart genes and environments So, you and me will have different personalities ? Why?

这在现实中是很难区分的,因为现实中很难,把基因和环境分开来讲,你和我有不同的性格,为什么？

耶鲁公开课 - 心理学导论课程节选

This proves Pythagorean Theorem.

这就证明了勾股定理

耶鲁公开课 - 死亡课程节选

When temperatures are hot, we are told this proves humans are creating a global warming crisis.

FORBES: NASA Data Pit Scientific Method Against Climate Astrology

According to alarmist groups, this proves global warming is much worse than previously feared.

FORBES: Ten Years And Counting: Where's The Global Warming?

This proves that with political will and the joint commitment of States, outcomes can be achieved.

UNESCO: Poverty is a Violation of Human Rights