Fortunately, she knew at once what to do.

　　幸運(yùn)的是，她立刻知道該做什么。

　　Fortunately, the clue is in the language itself.

　　幸運(yùn)的是，線索就在語言本身。

　　Fortunately, the collision hypothesis is testable.

　　幸運(yùn)的.是，碰撞假說是可驗(yàn)證的。