Since then he has not made any other public appearances, though he has occasionally responded to customer emails over matters such as the iPhone's apparent tracking of user location.

从那以后，他在再没在公开场合露面过，尽管他偶尔也会回复一些诸如iPhone明显的用户跟踪信息事宜等消费者邮件。

youdao

Since email addresses can change frequently, maintain the integrity of your email list by carefully tracking the number of bounce-backs or undeliverable emails after every campaign.

由于email地址可能经常改变，每次发送过后，记得要小心追踪退回邮件和发送失败邮件的数量已保证数据的完整可靠。

youdao

All they had to do was append a tracking code to their emails.

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