could use something idiom informal
（用来表示某人想要某物）
used to say that you would like something
I could use some help putting these decorations up if you're not too busy. 你如果不太忙的话，我想请你帮忙把这些装饰品挂起来。
"Can I get you anything?" "Thanks. I could use a drink." “我能给你拿点什么？”“谢谢，我需要一点饮料。”
（用来表示某人需要某物）
used to say that something or someone needs something
Their website could use an upgrade. 他们的网站需要升级了。
He could use a new suit for work. 他需要一套新西装上班。