I know, it is just a sentence to practise, but it would be more useful to eliminate the word "ezek" and "these".
I like your sence of humour :-)
A famous japanese philosopher once said: "Nothing is impossible!" smile
But there are no furry frogs at all on the world. It is a base characteristic of amphibian animals to be NOT furry.
That's why the sentence "These frogs are not furry" is not usefull at all.
But of course: this sentence is less rediculous than all of those with flying kindergarten teachers and cleaning ladies.