如图所示，某物体在一直线上运动的v－t图象。在0s-2s的加速度为 m/s2；后4秒的加速度为 m/s2。
3 ； -3 ；
There are also strange records, like the Englishman who ____ a small car ____ 159.6 kilogrammes ____
for thirty three seconds! [ ]
A. has balanced; weighed; on the head
B. balanced; weighed; by the head
C. balanced; weighing; on his head
D. had balanced; weighing; by his head
咨询服务按人月费单价法计费，人月费率中的利润按( )计算。
A．基本工资、社会福利和公司管理费三项之和的百分比
B．基本工资和社会福利两项之和的百分比
C．社会福利和公司管理费两项之和的百分比
D．基本工资和公司管理费两项之和的百分比
