In the rush to get to school, you drop a piece of toast on the floor. Do you throw it away or decide it’s still OK to eat? If you’re like most people, you eat it. Maybe you follow the “5-second rule”, which claims foods are safe to eat if you pick them up within 5 seconds after dropping them, but you might want to think again. Scientists now say that 5 seconds is all it takes for foods to become polluted with enough bacteria to make you sick.
Bacteria can cause many kinds of illnesses. Some kinds of bacteria can grow on food. If you eat foods on which these bacteria are growing, you can become sick.
One of these food-borne bacteria is Salmonella. It makes 1.4 million people sick every year. Salmonella is often found in raw eggs and chicken. Cooking kills these bacteria, which is why it is so important to cook eggs, chicken, and other foods thoroughly.
But how long does it take these bacteria to pollute food? A team of scientists in South Carolina did an experiment. First, they placed an amount of Salmonella on three surfaces; wood, tile (瓦片), and carpet. They placed a piece of bread and a piece of bologna（大腊肠） on each surface for 5,30 or 60 
seconds. After just 5 seconds, both the bread and the bologna picked up enough bacteria to make you sick.
So, forget the 5-second rule. If your toast drops on the floor, throw it away and get another piece of clean toast. This time, be careful not to drop it!
29、In which part of a newspaper can you most probably find this passage?
A．Culture B．Health C．Advertisement D．Technology
30、After dropping a piece of toast, a person who follows the “5-second rule” will. _______
A．throw away dirty toast immediately and go away
B．pick up the toast as quickly as possible and eat it
C．eat the toast within 5 seconds and feel pleased
D．get another piece of clean toast quickly and eat it
31、The underlined word “raw” in Paragraph 3 most probably means “_______”
A．delicious B．hot C．cheap D．uncooked
32、What’s the writer’s attitude to the “5-second rule”
A. Positive B. Negative C. Active D. Cautious