我进银行时，柜台前没有人，所以我不得不等待服务。

There was nobody at the ___counter when I went into the bank, so I had to wait to be served.

当我在柜台时，我放下包，付了餐巾纸的钱。

When I was at the ___counter, I put down my bags and paid for the serviettes.

在邮局，请到柜台寻求帮助。

Please proceed to the ___counter for assistance in the post office.