从某一高度处水平抛出一个物体，它落地时速度是50m/s，方向与水平方向成53°角．（g取10m/s²，cos53°=0.6，sin53°=0.8）求：

以下是加热盛固体药品的试管制气体时，检查装置气密性的主要环节，其顺序正确的是（   ）
①将手紧贴试管外壁，观察导管口现象
②将导管的另一端浸入水中
③移开手，观察导管内现象

计算下面各题。

20× $\frac{3}{5}$         $\frac{1}{7}$ × $\frac{2}{3}$            $\frac{2}{9}$ ×18          $\frac{4}{15}$ × $\frac{5}{8}$

    Little Tom likes cartoons very much .When the cartoons begin on TV, he does nothing until they' re over. Sometimes he'd rather wait for a long time and go to bed late. In the morning his mother has to wake him up, or he will be late for school.
    Yesterday Tom heard there would be an interesting cartoon today. This morning, as soon as he got up, he turned the television, but didn't receive the programme. He had to have breakfast and then went to school. After school he ran home while his mother was cooking supper in the kitchen (厨房). He hurried to the sitting room and turned on the television again, but he couldn’t find the cartoon. He rushed into the kitchen and asked his mother to help.
    “It's only five now,”said the woman. “Your programme will be after supper.”
    “Well, let's have supper right now!”