冒險的英語短語怎麼寫

例句：

投資航空公司是非常冒險的生意。

Investing in airlines is a very risky business.

這不是冒險的`時候，他知道他應該按規則行事。

This was not the time to take risks; he knew he should play it by the rule book.

這是一項冒險的舉動，但也許能換得更多的時間。

It was a risky operation, but might buy more time.