乐观的的英文：
brighter
brightest
optimistic
optimistical
upbeat

参考例句：

groundless optimism.
毫无根据的乐观

A sanguine disposition
乐观[快活]的天性

The best physicians are Dr. Diet, Dr. Quiet and Dr. Optimistic.
节食、恬静、乐观是最好的医生。

Look on the sunny side of everything
对每件事都抱乐观态度

I'm sanguine of success.
我对成功抱乐观态度。

All year she has fluctuated between optimism and despair.
全年当中她时而乐观，时而消沉。

"a cheerful person, to all appearances."
就表面迹象而论,是一个乐观的人

He has a sanguine attitude to life.
他对於人生有乐观的看法。

I then made some groundless remarks, assessing the situation over-optimistically
然后，我毫无依据地对形势作出了过于乐观的分析。

I really admire her indomitable optimism and can-do spirit.
我实在佩服她不屈不挠的乐观态度和苦干的精神。

brighter是什么意思：
adj. bright的比较级；更明亮的

" Brighter shopping, brighter prices "
明智的购物,透明的价格

The prospects for peace in the area are becoming brighter.
这个地区实现和平的可能性越来越大。

Some children are Brighter in one subject than in another
一些孩子在某课目上比另一科要学得快

brightest是什么意思：
adj. bright的最高级；最亮的

it shines the brightest where it is most fragile.
幸福是玻璃做成的，它最脆弱的地方最闪亮!

Sirius is the brightest star in the night sky.
夜空中最明亮的星是天狼星。

Stars shine brightest in the long dark night of winter.
星光照耀得最亮的时候，是在黑暗的冬夜。

optimistic是什么意思：
adj. 乐观的，乐观主义的

You have to be an optimist to be an inventor or entrepreneur.
要成为一位发明家或企业家，你必须得是个乐天派。

The timetable was hopelessly optimistic.
时间表制定得过于乐观。

An optimist sees the rose; a pessimist the thorn
〞乐观的人看到玫瑰,悲观的人只看到它的刺〞