请将这些信件投邮.Please take these letters to the post.将十封分属十个信封的信打乱,任意装进信封,并随便投邮.Ten letters that belong in 10 particular envelopes are scrambled and stuffed and mailed at random.使用投邮的办法必须在任何情况下是合理的.It must be reasonable in all...

“投邮”的英语可以翻译为：send by post，drop into a pillar-box ...