I know he is too optimistic but I don't want to depress him.是什么意思？

I know he is too optimistic but I don't want to depress him.

我知道他太过乐观了，但我不想令他灰心丧气。

know

v. 知道，了解，认识，确信；n. 知情；

例句
I know you're above me socially, but I must say I find your attitude offensive...
我明白你的社会地位比我高，但我得说我觉得你的态度很粗鲁。

he

pron. 他，它，一个人；n. 雄性动物；

例句
Logic had prevailed and he had abandoned the idea.
最终理智占了上风，他打消了那个念头。

is

vt.& vi. 是（be的三单形式；n. 存在；

例句
Bollinger 'RD' is a rare, highly prized wine.
博林格RD香槟是一种名贵的备受推崇的葡萄酒。

too

adv. 也，太，很，非常；

例句
The steep pavement was too narrow for them to walk abreast.
陡坡太窄，他们没法并排走。

optimistic

adj. 乐观的，乐观主义的；

例句
You will feel more buoyant and optimistic about the future than you have for a long time.
对于未来，你的感觉会比过去很长一段时间里更加自信和乐观。

but

conj. 但是，而是，除了，只因为；prep. 除…以外；adv. 只，不过，只是，另一方面；n. 借口，推辞，但是，反对；pron. [关系代词，意义相当于 who…not, which…not]；vt. 对…说“但是”；

例句
English food can be wonderful but the normal English diet is abominable.
英国也有美食，只是一般的日常饮食太过糟糕。

want

v. 想要，希望，打算，需要…在场；n. 需要的东西，缺少，贫穷；

例句
I want to be honest, honest above everything else.
我想要做到诚实，一切以诚实为上。

to

prep. 向，朝着，到，关于，属于；adv. 朝一个方向的，到某种状态，关闭；

例句
I suggest you leave it to an expert...
我建议你把它留给专家来解决。

depress

vt. 压下，压低，使沮丧，使萧条，使跌价；

例句
I know he is too optimistic but I don't want to depress him.
我知道他太过乐观了，但我不想令他灰心丧气。

him

pron. (he的宾格)他；

例句
They said goodbye to him as he got aboard the train at Union Station.
当他在联合火车站登上火车之际，他们向他道别。