A blonde detective
A policeman was interrogating 3 blondes who were training to become detectives. To test their skills in recognizing a suspect, he shows the first blonde a picture for 5 second and then hides it.

"This is your suspect, how would you recognize him?"

The first blonde answers, "That's easy, we'll catch him fast because he only has one eye!"

The policeman says, "Well...uh...that's because the picture shows his PROFILE."

Slightly flustered by this ridiculous response, he flashes the picture for 5 seconds at the second blonde and asks her, "This is your suspect, how would you recognize him?"

The second blonde giggles, flips her hair and says, "Ha! He'd be too easy to catch because he only has one ear!"

The policeman angrily responds, "What's the matter with you two?? Of course only one eye and one ear are SHOWING because it's a picture of his profile!! Is that the best answer you can come up with?"

Extremely frustrated at this point, he shows the picture to the third blonde and in a very testy voice asks, "This is your suspect, how would you recognize him?"

He quickly adds "...think hard before giving me a stupid answer."

The blonde looks at the picture intently for a moment and says, "Hmmmm...the suspect wears contact lenses."

The policeman is surprised and speechless because he really doesn't know himself if the suspect wears contacts or not. "Well, that's an interesting answer...wait here for a few minutes while I check his file and I'll get back to you on that."

He leaves the room and goes to his office, checks the suspect's file in his computer, and comes back with a beaming smile on his face. "Wow! I can't believe it...it's TRUE! The suspect does in fact wear contact lenses. Good work! How were you able to make such an astute observation?"

"That's easy," the blonde replied. "He can't wear regular glasses because he only has one eye and one ear."

A lecture about English
A linguistics professor was lecturing to his English class one day. "In English," he said, "A double negative forms a positive. In some languages, though, such as Russian, a double negative is still a negative. However, there is no language wherein a double positive can form a negative."

A voice from the back of the room piped up, "Yeah, right."