英语语句解释以及分析填空部分To some extent,it is the awareness of the importance of communication that leads to the invention of various means( by )which messages are set.1.请先解释一下这句的意思.2.括号中为什么用by?

Question

英语语句解释以及分析填空部分
To some extent,it is the awareness of the importance of communication that leads to the invention of various means( by )which messages are set.
1.请先解释一下这句的意思.
2.括号中为什么用by?

Answer 1

这是个强调句啊．
在某种程度上,是对交流的重要性的认识（重视）导致了各种各样的信息传播途径(方式）的发明．
by 这里是宾语从句,by which是关系代词,用by是因为先行词means ,means是用by修饰的,这时固定的介词短语,如by all means ,by this means等,倒过来看会更加明白,messages are set by various means(信息用各种方式传播）,另by可放在which前,也可放在set后．