He was always optimistic, even when things were at their worst.

　　他即使在情況最糟糕的時候也總是很樂觀。

　　We have every reason to feel optimistic.

　　我們完全有理由感到樂觀。

　　They are cautiously optimistic that the reforms will take place.

　　他們對是否實行改革表示審慎的樂觀。

　　She's not very optimistic about the outcome of the talks.

　　她對會談的結果不太樂觀。

　　When asked about the company's future, the director responded that he remained optimistic.

　　問到公司的未來的時候，經理回答說他依然樂觀。