英语寓言故事-The Frogs and the Well

Two Frogs lived together in a marsh. But one hot summer the marsh
dried up, and they left it to look for another place to live in: for
frogs like damp places if they can get them. By and by they came to
a deep well, and one of them looked down into it, and said to the
other, "This looks a nice cool place. Let us jump in and settle here."
But the other, who had a wiser head on his shoulders, replied, "Not so
fast, my friend. Supposing this well dried up like the marsh, how
should we get out again?"

"Look before you leap."