improbable

他赢得彩票的可能性很小。

It's ___improbable that he will win the lottery.

他说他中了一百万彩票，这听起来很不可思议。

His claim of winning a million-dollar lottery sounded ___improbable.

他编了一个难以置信的故事，说自己用纸飞机飞越了大西洋。

He made up an ___improbable story about crossing the Atlantic with a paper airplane.