在这个公式中，我们需要计算xx的值。

In this formula, we need to calculate the value of ___xx.

表格上有个叫xx的人填了联系方式，但号码是空号。

Someone named ___xx filled in the contact information on the form, but the number was invalid.

她在短信最后加了几个xx表示亲亲。

She added some ___xx at the end of the message to send kisses.