Ask for repairs in writing and keep a copy of the letter and response.

要求书面的备份，并保存一份信件和回复的复印件。

youdao

Some keep a copy of the data in all applications — both memory and swap space.

有些变体保留所有应用程序中的数据副本——同时包括内存和交换空间中的应用程序。

youdao

no-store —instructs caches not to keep a copy of the representation under any conditions.

no-store — 强制缓存在任何情况下都不要保留任何副本

youdao

Sometimes he did not even keep a copy of his book.

VOA: special.2010.01.10

Even after the matter is resolved, keep a copy of the notice with your return.

FORBES: Tax Tip #2: Dealing With IRS Notices

Keep a copy of the disc in your evacuation box and another copy in your safe deposit box.

FORBES: Are You Prepared for a Disaster?

Keep a copy of every return (and the canceled check, if you sent in money with it) indefinitely.

FORBES: Better buy yourself another filing cabinet