乐观的英文：
optimistic
hopeful
be positive

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。

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〞

Hope is the root of hopeful.
hope是hopeful的词根。

This is a hopeful sign.
这是一个乐观的信号。

We are hoping against hope for a change in her condition.
我们希望她的病情有一丝转机。

Moon is a positive.
月球是个实在的事物。

It is the positive of the battery.
这是电池的阳极

accessible position
可到达的位置