t1/angent释义：

n. 切线，切面正切

adj. 切线的，相切的接触的离题的

2/tangent用法例句：

The conversation went off on a tangent.

谈话突然偏离了正题。

A tangent is a straight line that touches the outside of a curve but does not cut across it.

切线是一条直线 它接触曲线的外部 但不横切它