29．We should study the new traffic rules and 1earn how___to protect___ ourselves．05云南这个句子是宾语从句吗?how to protect在句子中做什么成分 为什么是how 后面跟不定式

how to protect ourselves做learn的宾语。
how后面可以加上不定式

主语是We, 谓语是情态动词+动词原形，即Should+study/learn。The new traffic是study的宾语. How to protect ourselves是learn的宾语从句。（因为这句语里面有两个谓语，所以就有相对应的两个宾语或宾语从句了）
How to do something是作为宾语时的固定结构。
像这里的learn how to do..
还有ask how to do something, 等等。

learn 是个及物动词,后面要直接接宾语,learn something,这里的宾语由how引导的短句充当.疑问词how是询问方式方法,怎样保护我们自己.
疑问词（who,what,which,when,where,how）+不定式在句子中可以做主语,例如：When to start has not been decided.何时动身尚未决定.作宾语：
I don't know what to do .我不知道该怎么办.做表语：The question was where to go.问题在于到哪儿去.做双重宾语：I asked him how to learn English.我问他如何学习英语.具体选择哪个疑问词要看是对什么提问.

做宾语，how to do sth 固定搭配