我想洗个澡。用英语怎么说？

我想洗个澡。

I could do with a bath.

could

aux. “can”的过去式，能够，打算，用于假设语气的条件句，用于虚拟语气的结论句；

例句
The regulations were relaxed and the prisoners could get out and about a bit.
规定有所放宽，犯人可以出去短暂放风。

do

aux. 构成疑问句和否定句，代替动词，用于加强语气；vt. 做，干，进行，从事；vi. 表现，进展，引起，行过；n. 社交聚会，社交活动，宴会；

例句
Rachel was going to do something about Jacob...
蕾切尔将对雅各布有所行动。

with

prep. 和，跟，随着，关于，和…一致；

例句
A waiter entered with a tray...
侍者端着托盘进来了。

bath

n. 沐浴，洗澡，浴缸，澡盆，浸，泡，洗澡水；vt.& vi. （给…）洗澡；

例句
'I'm having a bath and going to bed,' she announced, and left the room.
“我要洗个澡然后上床睡觉，”她大声说完便离开了房间。