It can be very useful to understand.Etiquette is very import

It can be very useful to understand.Etiquette is very import but it can be very useful to understand中to understand是什么成分? 英语翻译it can be very useful ___ ____the meaning of "etiquette" Etiquette is a very important idea to understand英语翻译 英语翻译1.Etiquette is a very important idea to understand.2.We Fire can be very useful 英语翻译fire can be very useful,but it can also be very harmful the internet is very useful.we can use it( )english we find it is very useful to study english well This question is very difficult.( )people can understand it. 初三英语连词成句,单词有：it is,ads,that,some,very,can,true,be,useful 陈述句 He like it very much (b ) it is very useful to him.