" Now, Ben, he was a Roman — let me tell, " said Letty, using her elbow contentiously.

“现在，本，他是个罗马人——让我说吧，”莱蒂说着，用她的手肘争辩道。

More contentiously, you could argue they've been shaped by natural selection to solve certain problems.

更有争议的是，你可以说它们是通过自然选择来解决某些问题的。