it's a nice day (C.for) a walk. 表示理由或原因,意为“因为、由于”.如: Thank you for helping me with my English.谢谢你帮我学习英语. Thank you for your last letter.谢谢你上次的来信. Thank you for teaching us so well.感谢你如此尽心地教我们. 再问: 额,再问一个。Why ()learn English。 A.don't B.not C.not you 再答: B.not