It's very common throughout the internet. It may not be possible to know when it was first used. There are some variations on the phrase with the final word sometimes being "teach".
I've heard it in different forms:
"Them that can, do. Them that can't, teach." "Them as can, do. Them as can't, teach."
It is a rather snobbish opinion of teachers, and the teaching profession in...
"Are those they" is correct. "Are" is a form of the copulative verb "to be" and is not transitive. In this sentence it is linking two subjects; "them" is the accusative form of the pronoun "they,"...
It is easier to answer this question by means of examples:
Example 1:
1. What are those colors that you see in a rainbow? 2. They are violet, indigo, blue, green, yellow, orange, and red. Example...
I don't know if that's a proverb or not; I have heard it attributed as a quote from Mark Twain, and as a quote from Earl Ruby. The explanation is pretty easy, in my opinion. It simply means that if...