Often, it's best to check in both places; that way, if an attacker manages to slip around one defense, they'll still encounter the other.
通常，最好在这两处都对其进行检查；这样，即使一个攻击者成功地突破了一道防线，他们还会遇到另一条。
3
The critic calls attention to the way novelists slip sneakily in and out of their own prose, here speaking as a character, there pulling back the veil and revealing the voice of the author.