recipient-recipe-receipt-reciprocal

recipient
I like this in an email where you are trying to help the recipient. Looking forward
在试图帮助收件人的邮件中我喜欢这个。
recipe
The recipe for their drink is a closely guarded trade secret.
他们饮料的配方是严格保守的商业秘密。

receipt[rɪˈsiːt]  注意p不发音

Keep your receipt as proof of purchase.
保存好收据作为购货凭证。
reciprocal [rɪˈsɪprəkl]
The two colleges have a reciprocal arrangement whereby students from one college can attend classes at the other.
两所学院有一项互惠协定，允许学生在院际间选课。


A material's capacity to conduct electricity; measured as the reciprocal of electrical resistance.
一个物质的导电能力；用电阻的倒数来衡量。