@Chen Ta,
Quote:Is this sentence correct ?
Your idea about "mergers" is fine, but your sentences are not quite right.
"The man who wears a sunglasses eat a burger which is made by pork."
Assuming this is past tense, you might say: The man wearing sunglasses (not "who wears) ate (not eat--present tense would be "eats") a pork burger.
:"The man who wears a sunglasses which is flip-up style eat a burger"
Same deal here: The man wearing flip-up style sunglasses ate (or eats) a burger.
You could also say: The man
who wore sunglasses was eating (or ate) a burger (past tense). But you would not say "who wears"--you would just say "wearing."
You could say "the man who was wearing," but the "who was" would be unnecessary clutter.