Provide tracking no. & confirm with receiver after shipment.

提供相关运单并与供应商确认是否收到货物。

There should be absolutely no behavioral tracking of minors.

对于未成年人应该是完全没有的行为跟踪的。

This is extremely difficult to do, as humpbacks are too large to be put in captivity for study, and no good methods for tracking individual mating patterns exist.

由于座头鲸个头太大， 无法在密闭的环境中进行研究， 并且也没有跟踪单个交配模式的好方法， 所以对研究人员来说完成这项工作实属不易。

I have found that being able to report these exceptions with a specific error code (instead of a generic exception or, even worse, no reported error) has saved me hours tracking bugs.

我发现，在跟踪错误时，用特定的错误码(而不是一般的异常或—甚至更糟—不报告错误)来报告这些异常节省了我数小时的时间。