A:①②
B:②③
C:①③
D:①④
下列物质中,不属于有机高分子化合物的是( )
任务型阅读Mrs. Wilson is not tall with curly hair. She comes from Australia. She is our math teacher. But I don't like math. It's too difficult and boring. Mrs. Wilson is 25 years old. She is very shy (害羞)and kind of serious(严肃的). She never plays games with us. She often sees the films on weekends. And she enjoys reading very much. She has lots of books in her bedroom.根据短文内容填表。1____、2____、3____、4____、5____.
已知直线a,b被直线c,d所截,a∥b,且直线c⊥直线a,直线d⊥直线b,则直线c与直线d之间的位置关系是____ .(填“平行”“相交”或“垂直”)