我觉得，这句话本身有问题，不知你从哪里得到这个句子的？

But I did anything I could to make the new pups clean and feel good.

——本句使用anything不正确，换成everything才是对的！

我认为，do anything用在肯定句是可以的，但前提是：do anything 这个动作应该是个“虚拟的未实现的动作”，而不是“已经实现的动作”，所以，我们可以说：

I will do anything...

I can do anything...

I would do anyhting...

I could do anyhting...

I am ready to do anything....

I am willing do do anyhting...

If I do anything ...

以上句子表达的do anything 并未真正实现。

但不能说：I did anything ... 我已经做了任何事情？？？