Kí ni ọ̀rọ̀ àpẹẹrẹ nínú gbolohun: Òjò ń rọ bí i pé ọ̀run ń șú?

In the sentence Òjò ń rọ bí i pé ọ̀run ń șú (the rain is falling as if the sky is pouring), the speaker is not stating a fact directly but comparing the intensity of the rain to an imagined event. The phrase that introduces this comparison is bí i pé, which means "as if" or "as though."

This phrase is what grammarians call the comparison marker: it signals that what follows is not literally true but is used to intensify the description of the rain. The remaining words in the sentence, òjò (rain), rọ (to fall/rain), and ọ̀run (sky), simply name the things being talked about; none of them performs the work of setting up a comparison.

When a question asks for the comparison word in a Yoruba sentence, look first for a phrase built around bí (like/as), since that is the standard way Yoruba introduces a simile.