How much less would it cost to send it second class?用二类邮件寄，会省多少钱？Unfortunately it was sent second-class, so it hasn't arrived yet.不幸的是，它是作为二类邮件邮寄的，所以至今还没有寄到。I sent the parcel second-class.我把这包裹按二类邮件寄出。How much does it cost for second class?寄二类邮件要多少钱？