expedient

n. 权宜之计,临时手段
a. 权宜的,方便的,有用的

He thought it expedient not to tell his wife where he had been.

他认为不告诉妻子他去过哪里是适宜的。

As he had forgot his keys, he got into the house by the simple expedient of climbing through the window.

他由于忘了带钥匙，便以简单的应急办法从窗户爬进屋里。