题干
Your donation_________ and the money will be used to help the students from poor families.
A：is greatly appreciating
B：appreciate
C：has appreciated
D：is greatly appreciated
答案(点此获取答案解析）
D
。现将重物向下拉
，然后放手，则在刚释放的瞬间，重物加速度的大小是（
=
）
