单项选择题假设一个静止质量为m0、动能为的粒子同静止质量为2m0，处于静止状态的粒子相碰撞并结合在一起，则碰撞后结合在一起的粒子的质量： A、 B、 C、 D、
单项选择题If the liabilities of a business increased 30,000 during the same period, the assets of the business must have: A、Decreased 45,000. C、 Increased 45,000. E、Increased $105,000.
