她对赢得金牌的机会持乐观态度。

She is ___optimistic about her chances of winning a gold medal.

我对他们是否足够敏感地尝试生产更少的汽车，把人类生命放在利润之前，并不非常乐观。

I'm not very ___optimistic about them being sensitive enough to try to produce [fewer] cars, putting human life before their profits.

尽管面临挑战，他对未来仍然持乐观态度。

Despite the challenges, he remains ___optimistic about the future.