题干
� Many a man ________ swimming in the river, but only ________ can swim across it
A：go… a few
B：goes… a few
C：go… few
D：goes… Few
答案(点此获取答案解析）
B
A：go… a few
B：goes… a few
C：go… few
D：goes… Few
时刻，将一金属小球从弹簧正上方某一高度处由静止释放，小球落到弹簧上压缩弹簧到最低点，然后又被弹起离开弹簧，上升到一定高度后再下落，如此反复。通过安装在弹簧下端的压力传感器，测出这一过程弹簧弹力
随时间
变化的图象如图 (乙)所示，则（ ）