题目内容：

阅读下列短文, 从每小题的A、B、C、D四个选项中选出最佳选项。

D

Almost everyone has dropped some food on the floor and still wanted to eat it．If someone saw you drop it, he or she might have shouted, “ 5-second rule!” This so–called rule says food is OK to eat if you pick it up in five seconds or less．But is that true?

Professor Anthony Hilton from Ashton University, UK, tested the rule with his students．They found that food dropped for five seconds is less likely to contain bacteria(细菌) than if it sits there for longer.

For the study, Hilton and his students tested a lot of foods——bread, pasta, cookies and candy—to see how much bacteria they had when they made contact with the floor．They allowed the food to lie on the different types of flooring—carpet(地毯), laminate (复合地板) and tile(瓷砖) — for three seconds to 30 seconds.

Not surprisingly, the longer the food was on the floor, the more bacteria it had．And the type of floor where the dropped food landed had an effect．Bacteria are least likely to transfer(转移) from carpet, while they are most likely to transfer laminate or tiled surface after more than five seconds．

The study also found that the wetter the food, the more likely it was to pick up bacteria．Although most people are happy to follow the 5-second rule, eating food dropped on the floor still carries an infection(感染) risk．“It very much depends on which bacteria are on the floor at the time.” Hilton told Forbes．

1.What is the “5-second rule’ mean?

A．People often shout at someone when they drop food on the floor.

B．Food is safe when you pick it up off the floor in less than five seconds.

C．It’s better to eat dropped food when it’s been on the floor for over five seconds．

D．Food will go bad when dropped food on the floor in five seconds or less．

2.Where is Ashton University?

A．In the USA.

B．In England.

C．In China.

D．In France.

3.Hilton’s test wanted to find out____________.

A．if the “5-second rule” is true

B．the students’ favorite food

C．which food is easily dropped

D．if different types of floor have different bacteria

4.According to the test, we learn the following EXCEPT ________．

A．the dropped food had more bacteria if it sat on the floor for longer.

B．the dropped food on the carpet had the least bacteria.

C．bacteria was impossible to transfer from laminate or tiled surfaces.

D．the wetter food was likely to pick up bacteria.

5.According to the article, the infection risk of the dropped does NOT depend on _____________.

A．how long the food sits on the floor

B．what the dropped food is

C．what the bacteria are

D．what the weather is like that day