Word Puzzles

It is easier to recognize a sentence from its consonants than from it's vowels. For instance, try to read the following sentence in which the consonants are left out:

_ _ A Y I _ _       _ O _ _       _ A _ E _       I _       A       _ O _       O _       _ U _ .

Not easy, is it? Now consider the same sentence with the consonants in and the vowels left out:

P L _ _ _ N G       W _ R D       G _ M _ S       _ S       _       L _ T       _ F       F _ N .

I bet you figured it out that time, didn't you? Even though there are roughly the same number of vowels as consonants in the sentence, you could probably figure out the sentence with the vowels left out but not with the consonants left out.

Here are some well-known sayings that you have undoubtedly heard in which I have left out the vowels to see if you can figure out what they are. However, being the piss-ass that I am, and not wanting to make things too easy for you, what I have done, instead of leaving the spaces in between blank, is to insert random consonants where the vowels are supposed to be. (Tricky, ain't I?) Now you have to try to figure out which are the bogus consonants before you can insert the vowels to make the sentence. Not so easy! Have fun trying, though.

Note: Since I am using a computer program to replace the vowels, and the computer is unable to distinguish between a Y-vowel and a Y-consonant, I am leaving Y's alone, so that will perhaps make your job just a tad bit easier. Ditto for W's. I only replace the 5 vowels A, E, I, O and U. Also, of course, I hope that these sentences all being rather well-known sayings will help make your job easier.

What is the following sentence/saying?

Bxttxr thl drvhl ymk knmw thxn thn dsvnl yvz dcn't kncw.