沪友详解A：
carry the ball来源于橄榄球运动,指“持球前突”，即一个运动员持球往对方底线方向冲，其余队员掩护并伺机传球，因此在美国口语里，此短语表示“承担主要任务”，如：Some good friends are carrying the ball for us.（几个好友在为我们挑重担。）

沪友详解B：
carry the ball= to take the shame or responsiblity for sth that is wrong or has not succeeded.

例句
1、You can count on Jim to carry the ball in an emergency.在情况紧急时，你总是可以依靠吉姆负起主要责任的。
2、any of various games played with a ball (round or oval) in which two teams try to kick or carry or propel the ball into each other's goal.
任何一种用球的运动（圆形或椭圆形）两队尽力去踢球或抢球。
3、None of the other boys would tell the principal about their breaking the window, and Henry had to carry the ball.
其他孩子没有一个愿告诉校长打破窗户的事，亨利只好挺身而出。