网络安全策略包括 【15】 、先进的技术和严格的管理。

根据短文内容，用方框所给单词的适当形式填空，每词限用一次。

they   subject   from   know  how

Many people go to school for a good education(教育). They learn languages, history, math, art and other ___81_____. School education is very important and useful, yet no one can learn everything ___82_____ school. No matter(不管) how much a teacher ____83____, he can’t teach his students everything they want to know. His work is to show his students ____84____ to learn. He teaches ____85____ how to read and how to think. So, much more is to be learned outside school by the students themselves.