题目

若tan α＜0，则（ ）                                         A．sin α＜0        B．cos α＜0                             C．sin αcosα＜0   D．sin α﹣cos α＜0                                                                              4km2=______m25200cm=______m1L-130mL=______mL6007kg=6t+______kg．