题目内容：

    If someone is crying in an attempt to fake sorrow, we say they are shedding “crocodile tears”. But how and why did we start relating insincere displays of feelings to crocodiles?

The origin may have become popular around the 14th century when a bestseller, The Voyage and Travel of Sir John Mandeville, referenced a kind of snake who drops tears while eating their human victims.

In the centuries since, crying crocodiles have been related to fake sorrow. The expression has been used as a story to teach sincere regret, by Shakespeare and, more recently, by media mocking tearful politicians or murder suspects.

In 2007, University of Florida zoologist Kent Vliet actually proved that the animals do drop tears while snacking. But because crocodiles eat while in the water—making a study of their meal-time tears difficult—he studied their close relatives, alligators, who might dine on dry land. Out of the seven he filmed eating at a Florida alligator park, five teared up before, during, and after eating.

Vliet’s theory is that when the animals enthusiastically hit their jaws, the movement forces air through the crocodiles’ sinuses and finally empties tears into their eyes. Their eyes not only water but can bubble, as Vliet witnessed at the alligator park, where some even teared up in expectation of their meal of chicks and other food.

Vliet was asked to investigate the biology behind this phenomenon by Malcolm Shaner, a doctor, about why facial palsy sufferers cry when they chew. Findings suggest that this is similar to the case of crocodiles.

1.What does “crocodile tears” express?

A.False sadness. B.Sincere apology.

C.Untrue suffering. D.Faithful concern.

2.Who has studied humans’ shedding tears while chewing?

A.John Mandeville. B.Shakespeare.

C.Kent Vliet. D.Malcolm Shaner.

3.What's the meaning of the underlined word “mocking” in Paragraph 3?

A.Teasing. B.Reporting. C.Fooling. D.Comforting.

4.What's the author's purpose in writing the passage?

A.To describe the physical appearance of crocodiles.

B.To give a biological explanation of crocodile tears.

C.To clarify a misunderstanding of political leaders.

D.To introduce results of research on human feelings.