Always the _____, Franklin believed the practice of moving the time could save on the use of candlelight, as candles were expensive at the time. A . journalist B . physicist C . chemist D . economist 答案:D指出下列事件是必然事件、不可能事件,还是随机事件.
(1)如果a>b,c>d,则 a-d>b-c;
(2)对某中学的毕业生进行一次体检,每个学生的身高都超过2米;
(3)某电视剧收视率为40%;
(4)从10个玻璃杯(其中8个正品,2个次品)中,任取2个,2个都是次品;
(5)在不受外力作用的条件下,做匀速直线运动的物体改变其匀速直线运动状态.