what does this sign mean? it tell us ____ here

what does this sign mean? it tell us ____ here what does this sign mean? What does it mean What does this sign mean意思一样吗? What does this sign mean?Where ca What does this sign mean?Where Could someone tell me what does this sign mean in mathematic What does this sign mean?可以写成 what is this sign mean?为什么? does,it,keep,what,off,grass,this,the,sign,mean,means(?.) does,it,kepp,what,off,grass,this,the,the,sign,mean,means(?.) What does this sign mean?换一种表达 What does that sign mean? what does the sign mean.