1. A research institute spent nine years tracking and investigating the eating habits of 63,000 healthy people, including the consumption of meat, cooking methods and the degree of maturity of meat. The research team divided the subjects into five groups according to the amount of barbecue. By the end of the study, 208 people had pancreatic cancer, most of whom were concentrated in the two groups with the highest barbecue consumption. Therefore, the researchers concluded that eating a lot of barbecue is more likely to develop pancreatic cancer.

Which of the following, if true, can weaken the above conclusion most?

A study shows that if one parent has pancreatic cancer, the chances of a child suffering from the disease will increase by 30%.

B. Explain that compared with people who eat cooked meat and barbecue for a long time, the proportion of pancreatic cancer is similar.

According to the survey, 98% of people who eat barbecue in large quantities like to eat barbecue while drinking beer and often stay up late.

D In this study, the proportion of pancreatic cancer in people who prefer semi-cooked barbecue is about 60% higher than that in people who prefer full-cooked barbecue.

2. The research team led by Shouye Jiuye, an associate professor at the Graduate School of Gifu University, and Zhuo Yoshida, director of the East China Sea Cell Research Institute of Gifu City, made the experimental mice suffer from colorectal cancer. In the following 13 weeks, the researchers put three different concentrations of water-soluble magnesium into some experimental mice. Results The number of cancer cells in the experimental mice treated with 7 ppm (65 65,438+0 ppm is one in a million) was only half of that in the control mice without any treatment, while the number of cancer cells in the experimental mice treated with 65,438+0.75 ppm of water-soluble magnesium was reduced to one quarter of that in the control mice. Researchers speculate that chromosomes are unevenly distributed when cancer cells divide. It is the instability of this gene that helps the proliferation of cancer cells, and water-soluble magnesium can alleviate this instability, thus inhibiting the proliferation of cancer cells.

The following statement is consistent with the meaning in the text:

A. In the experiment, mice receiving higher concentration of water-soluble magnesium have the least cancer cells.

B. The researchers are going to carry out the experiment that water-soluble magnesium can control the proliferation of cancer cells.

C. Because water-soluble magnesium is relatively stable, it can inhibit the proliferation of cancer cells.

The water solubility of magnesium can inhibit the proliferation of cancer cells.

3. Xiaoli, Xiaomei, Xiaoxing, Xiaozhen and Xiaolong play together, and some children have mud on their foreheads. Obviously, every child can only see if there is mud on other people's heads, but can't see if there is mud on his own head. Children with mud on their heads can only tell lies, and children who can only tell lies must have mud on their heads. Similarly, a child without mud on his head only tells the truth, and a child who only tells the truth must have no mud on his head. Known:

Xiaoli said: I saw three people with no mud on their heads and one with mud on their heads.

Xiaomei said: I saw four people with mud on their heads.

Xiaoxing said: I saw four people with no mud on their heads.

Xiaolong said: I saw one person with no mud on his head and three people with mud on his head.

Therefore, the following statement must be correct:

A. there is no mud on Xiaoxing's head.

B. Xiao Li and Xiao Zhen have no mud.

C. Xiaomei has mud on her head.

D. Xiaozhen and the small faucet are covered with mud.

Reference answers and analysis

1, answer C. Analysis: Is the stem of the question obtained through research? Eat a lot of barbecues? And then what? Pancreatic cancer? There is a causal link between them. C shows that people who eat more barbecue have other differences compared with others, except the amount of barbecue, which may lead to pancreatic cancer and weaken the conclusion. A, the relationship between parents and children, and D's preference for half-cooked and full-cooked, have nothing to do with the consumption of barbecue; B it looks relevant, but? Eat barbecue for a long time? With what? Eat a lot of barbecues? Not a concept, crime? Stealing the concept? This mistake. So the answer is C.

2. Answer A. Analysis: Analysis options, what are the options A? Higher concentration? As long as you pay attention to the determination, you can prove whether option A is correct. 7ppm and 175ppm are obviously related to the concentration, which proves that option A is correct. Option b should focus on? Are you ready? This word describing tense is incorrect because it has already happened. What should I pay attention to in option C? Because, so? Such related words have no causal relationship, so this option imposes causal relationship, which is incorrect; Option d can be obtained from? Water-soluble magnesium can alleviate this instability and thus inhibit the proliferation of cancer cells? The comparison seems correct, but inhibiting water-soluble magnesium does not mean inhibiting water-soluble magnesium, which makes the mistake of stealing the concept. Therefore, the correct answer is a.

3. answer C. analysis: from the stem of the question, we can find that if there are four people, they can provide us with clues, but the problem is that we can't determine who has mud and who is telling the truth, so we can quickly determine to use the hypothesis method to solve this problem. But the crux of the problem lies in which condition to assume. After combing the conditions, we can know:

Xiaoli said: I saw three people with no mud on their heads and one with mud on their heads. (None for 3 people 1 person)

Xiaomei said: I saw four people with mud on their heads. (4 people have)

Xiaoxing said: I saw four people with no mud on their heads. (4 people did not)

Xiaolong said: I saw one person with no mud on his head and three people with mud on his head. (1 3rd person has)

Through simple analysis, we can find that at this time, if what Xiaoli said is true, that is, three of the other four people don't have 1, but at this time, we can't be sure who the other four people have mud, and four situations can't be solved in a short time. Therefore, we will not give priority to small profits and dragons as the starting point of the hypothesis. And if we assume that what Xiaomei said is true, we can know that the other four people are all muddy and lying at this time, so we can proceed to the next step of reasoning. At this time, we found that Xiaolong's statement was consistent with our hypothesis, so Xiaolong also told the truth at this time, but if the first step assumes that there is mud on the small faucet, we should tell a lie. If there is a contradiction, Xiaomei can't tell the truth, so we know that Xiaomei has mud on her head and choose option C.