fruit與be動詞的用法

如果你要把fruit 運用到be中

你可以詢問他人最喜歡的水果是什麼

what are(be 的複數形式are) your favourite fruit?

my favourite fruit is apple.

詢問他人的朋友最喜愛的水果是什麼

what is (be 的單數形式is)your mother's favourite fruit?

her favourite fruit is pineapple.