various kinds of和a variety of后面加[c]?[u]?

various kinds of+【cn；pl】可数名词复数；【unc.n】不可数名词.
a variety of+ 【cn；pl】可数名词复数/【unc.n】不可数名词.例如：
Because of this,they can't repair the various kinds of damage they need,or create the amino acids and proteins they need.
他们不能修复各种损伤,或者生成所需的氨基酸蛋白质
So look,why am I justified in believing in germs,various kinds of viruses that I can't see,or bacteria or what have you,that I can't see?
所以,我为什么相信微生物,相信各种肉眼无法看到的病毒,细菌等诸如此类我看不到的东西确实存在.
Willett is a very prominent nutrition researcher and his name will come up in a variety of context in the class.
沃尔特是一名出色的营养学研究员,以后的课会经常提到他的名字
There is no one-size-fits-all model of political life but good regimes may come in a variety of forms.
政治生活并没有大小通吃的模式,但好的政体,可能以各种形式存在.