【单选题】In the standard (x,y) coordinate plane, the midpoint of AB is (4,–3) and A is located at (1,–5). If (x,y) are thecoordinates of B, what is the value of x+y?
【简答题】The year 2005 is the midpoint of a decade that spans three unique, important transition in the history of humankind. 【S1】______ Before 2000, young people always outnumber old people. 【S2】______ From 2...