I'd like to send this by air mail, please.　

我想要用航空郵寄這個，麻煩你。

by air mail寄空運

by sea mail寄海運

by regular mail寄平信

by registered mail寄掛號

by special delivery寄限時專送

=by express delivery

例:It's cheaper to send a package by sea mail than by air mail.

　 (用海運寄包裹比寄空運便宜。)

　 I want to send the letter by special delivery.

　 =I want to send the letter by express delivery.

　 (我要用限時專送寄這封信。)

注意:

mail n. 郵件 & vt. 郵寄

mail作名詞時, 表各種郵件的總稱 (包括信及包裹), 為不可數名詞; 作動詞時表『郵寄』。

mail a letter　　寄一封信

=send a letter

=post a letter

例: I usually receive many mails every day. (╳)

  → I usually receive a lot of mail every day. (○)

　 (我每天通常都會收到很多郵件。)

　 Please mail the letter for me.

　 =Please send the letter for me.

　 =Please post the letter for me.

　 (請幫我寄這一封信。)

You can't seal the envelope, though.　不過你不能把信封封起來。

a. seal是動詞, 表『(密) 封』的意思。

例: Seal the letter before you mail it.

　　(寄信之前要把信封好。)

b. though有下列兩種重要用法:

1)作副詞, 表『不過、然而』, 使用時通常置於句尾, 前面加逗點。

　＊本句的"You can't seal the envelope, though."即為此種用法。

例:A: Can I borrow your bike?

　 B: Yes, you can. Don't break it, though.

　 (甲：我可以向你借腳踏車嗎？)

　 (乙：是的，可以。不過別把它弄壞哦。)

2)作連接詞, 表『雖然』, 通常置於句首。但要注意的是:

中文的句法有『雖然……, 但是……』的習慣用法, 但英文中卻不能用"Though..., but..."的句構, 因為though和but都是連接詞, 依英文文法規則, 一句中只能有一個連接詞, 故用though就不能再用but。相同的情形亦發生在『因為……, 所以……』的句法, 英文中不能用 "Because..., so..."的句法, 而只能用其一。

例: Though he is nice, but I don't like him. (╳)

　→ Though he is nice, I don't like him. (○)

　　=He is nice, but I don't like him.

　　(雖然他人很好，但是我不喜歡他。)

　　Because he is nice, so I like him. (╳)

　　→Because he is nice, I like him. (○)

　　=He is nice, so I like him. (○)

　　(因為他人很好，所以我喜歡他。)