3.When prices go up, sales go down. And when the sales go down, factories cut production and ( ) workers.

　　A. lay out

　　B. lay off

　　C. lay against

　　D lay on

　　【答案】B。句意为：价格上涨时，销售下降。当销售下降时，工厂削减了生产和裁人。A.布局，B.裁员，C.反对，D.躺在。所以答案选B。