什么情况下用that引导的主语从句

什么情况下用that引导的主语从句
我能理解that在句子中间的句型,可有些是用在句首,算什么,又不作句子成分,难道作语气词?还是语言习惯?
比如：
That the equipment of modern camping becomes yearly more sophisticated is an entertaining paradox for the cynic
That the college will get in more new students this year is ture.
写道这好像有点感觉,是不是这个that有一种隐隐约约作主语的意思,像第一个句子如果不用that是不是要改成这样：
The equipment of modern camping becoming yearly more sophisticated is an entertaining paradox for the cynic.
就是说that可以省略的？