This is _____difficult problem______my brother can't work it out.A.so,that B.such,that C.so a,that D.such a,that

This is is this This is THIS IS this is this is this is 比如 this is fly Is this a book? Yes,this is. This is life .This is live! This is Mary.意思不变：This is （ )( ) This Is Me,This Is You 歌词 This is a man提问( ) is this? this is kangkang.为什么用this is 《This is my This is my This is (he).This is (me). what is this?-It is. What is this?It is Is this?your friend is