To deface (writing) by drawing lines across it.

划线勾销。

To mark so as to render valueless, as a stamp.

盖注销戮使之作废(如邮票)。

To annul, as a contract.

废弃(合同)。

To withdraw, as an order.

取消(命令)。

To strike out, as in taking out a common factor from the numerator and denominator of a fraction.

【数】消去；约去(如数学中之公因数)。