Food picked up just a few seconds after being dropped is less likely to contain bacteria(细菌) than if it is left for longer periods of time, according to the findings of research carried out at Aston University’s School of Life and Health Sciences. The findings suggest there may be some scientific basis to the “5 second rule” --- the belief about it being fine to eat food that has only had contact with the floor for five seconds or less. Although people have long followed the 5 second rule, until now it was unclear whether it actually helped.
The study, undertaken by final year Biology students and led by Anthony Hilton, Professor of Microbiology at Aston University, monitored the transfer of the common bacteria from a variety of indoor flooring types (carpet, cement floor etc.) to toast, pasta, a biscuit and a sticky sweet when contact was made from 3 to 30 seconds. The results showed that: Time is a significant factor in the transfer of bacteria from a floor surface to a piece of food; and the type of flooring the food has been dropped on has an effect, with bacteria least likely to transfer from carpeted surfaces and most likely to transfer from cement flooring surfaces to moist(湿的) foods making contact for more than 5 seconds. Professor Hilton said: “Consuming food dropped on the floor still carries an infection risk as it very much depends on which bacteria are present on the floor at the time.”
The Aston team also carried out a survey of the number of people who employ the 5 second rule. The survey showed that: 87% of people surveyed said they would eat food dropped on the floor, or already have done so. 55% of those who would eat or have eaten food dropped on the floor are women. 81% of the women who would eat food from the floor would follow the 5 second rule. Professor Hilton added, “Our study showed that a surprisingly large majority of people are happy to consume dropped food, with women the most likely to do so. But they are also more likely to follow the 5 second rule.”
According to the passage, which of the following is true?

A．A toast dropped on the carpet is easier to be polluted than that dropped on the cement floor.

B．A sticky chocolate dropped on the carpet is easier to be polluted than that dropped on the cement floor within 5 seconds.

C．The food dropped on the carpet shares the same potential of being polluted with the food dropped on the cement floor.

D．The food dropped on the cement floor is not as safe as food dropped on the carpet within 30 seconds.

Eating food dropped on the floor still carries an infection risk because it relies on _________ at that time.

A．the type of bacteria

B．the carpet

C．the cement floor

D．the surface of table

The passage is developed probably by __________.

A．time	B．space
C．contrast	D．example

What is the main idea of this passage?

A．The food which is dropped on the floor can be eaten safely.

B．The bacteria have no negative effect on the safety of food.

C．A research on the safety of food dropped on the floor is undertaken.

D．People surveyed in the research are willing to accept the idea.