— Mr. Hurst, could I join in your after-class activity from tomorrow on?
— Of course, Jenney. You can come every Tuesday and Friday afternoon.
A:take part in
B:cheer up
C:guard against
如图所示,A、B两条直线是在A、B两地分别用竖直向上的力F去拉质量分别为mA和mB的两个物体得出的加速度a与拉力F之间的关系图线,由图线可知( )
①例:他跑到周围的山里找到泉水,又砍了些竹子。
②例:要是能往泥塘里引些水,就能卖出去了。