L3：
讲座
1. What is the main purpose of the lecture?
To contrast the functions of probiotics and antibiotics
To describe some ways that bacteria contribute to human healt
To describe some differences between beneficial and harmful bacteria
The explain the relationship between bacteria and vitamins
2. The professor mentions research findings on the number of bacterial cells in the human body. What is her opinion of these findings?
She is confused by the inconsistency of the various findings.
She accepts the validity of the findings.
She expects that future research wilt show that the estimates are too high.
She regrets that researchers did not include counts of bacteria in the digestive system.
3. According to the professor, what are the main functions of beneficial bacteria that normally live in the digestive system?（多选题）
They help the body process complex carbohydrates.
They consume the bacteria that cause digestive problems.
They produce some vitamins that the body cannot make on its own.
They slow down the absorption of proteins.
They prevent bad bacteria from obtaining enough nutrients.
4. What does the professor imply about the use of antibacterial soap? A.
It may increase the risk of an infection.
It is not very effective in killing bacteria.
It is effective only if used on a regular basis.
It provides the skin with an added layer of protection.
5. What point does the professor make about the bacteria present in yogurt?
A. The bacteria can cause sickness in some people.
B.The bacteria in some yogurt brands are difficult to digest.
C.Live bacteria are not present in all yogurt brands.
D.The bacteria act like an antibiotic in the digestive system.
6. What does the professor imply about probiotics?（多选题）
A. They can help fix problems caused by antibiotics.
B.They will eventually replace antibiotics.
C.They probably cause more harm than good.
D.Evidence is lacking for certain claims about probiotic supplements.
