From Twitter:
What's the usual expression?
① What did you have for lunch?
② What did you chow for lunch?
③ What did you eat for lunch?
④ What did you had for lunch?

The
日本語訳
問題の日本語訳
「昼ごはんに何を食べた?」の普段の言い方はどれでしょう。① What did you have for lunch? ② What did you chow for lunch? ③ What did you eat for lunch? ④ What did you had for lunch?
解答・解説
answer and explanation is: ① 'What did you have for lunch?' We don't usually say 'eat' (choice ③) unless we want to focus on the physical act of consuming food or unless the listener(s) did not hear 'have' after several attempts to ask.原文の推奨は① What did you have for lunch?。eat を使う③も文法上は正しく、食べる行為を特に強調するときなどに使えます。④は did の後に過去形 had を置いているので誤りです。原文では、have が聞き取られないときに eat を使う場合にも触れています。