By contrast, if M(t) denotes the amount of money in a bank account at time t, then the function jumps at each point in time when money is deposited or withdrawn, so the function M(t) is discontinuous.
”相比之下，如果 M ( t ) {\displaystyle M(t)} 表述在时间t的时候银行账户上的钱币金额，则这个函数无论在存钱或者取钱的时候都会有跳跃，因此函数 M ( t ) {\displaystyle M(t)} 是不连续的。