— Because he was ________ to reach the apples on the tree.
A:too short
B:short enough
C:too tall
D:long enough
在塔顶上将一物体竖直向上抛出,抛出点为A,物体上升的最大高度为20m.不计空气阻力,设塔足够高.则物体位移大小为10m时,物体通过的路程不可能为( )
请将①~⑤的病症分别与其对应的病因A~E对应起来.
①侏儒症____ A营养物质缺乏
②佝偻病____ B激素分泌异常
③艾滋病____ C冠状动脉堵塞
④关心病____ D病毒性感染
⑤白化病____ E遗传物质发生改变