这儿有一只狗用英文怎么说

Here is a dog 被翻译为 "There is a dog"。

这是一种常见的说法，表示当前位置有一只狗。

例句：

"There is a dog barking outside." (外面有一只狗在叫)
"Look, there is a dog running in the park." (看，公园里有一只狗在跑)
"I saw a dog when I was walking down the street." (我在街上散步时看到了一只狗)