convenience function的用法和样例：
例句
- A tabulation of a function of two variables is cumbersome, but possible.
二元函数的列表法是不方便的，然而是可能的。 - The utility cost function is considered, which includes the increase of trip expense and trip time, reduction of comfort and decrease of convenience during the transfer.
该效用损失函数充分考虑了居民换乘导致出行时间和费用的增加以及舒适性和方便性的损失。
