2026届高考英语一轮复习外刊精读与练习Day 11 猫和狗吃草真的是为了治病吗导学案

Why do cats and dogs eat grass?

猫和狗吃草真的是为了治病吗

改编自：生活科学

Article

Main idea

Dogs and cats often chew grass, yet scientists still argue about the reason. One popular belief says pets use grass as a natural medicine to calm an upset stomach. Surveys, however, do not support this idea. In 2008, researchers asked 1,571 dog owners about plant-eating; 68 % said their dogs munched on grass at least once a week, but only 8 % noticed signs of illness beforehand. Two later studies on cats reported similar figures: only 6–9 % of the animals seemed sick before grazing, although about one-third vomited afterward. These data suggest that nausea is rarely the trigger.

提出“猫狗吃草”这一看似矛盾的现象，引出全文讨论的核心问题——原因何在。

A second theory claims that fibrous grass helps cats cough up hair balls or helps both species flush intestinal parasites. Yet the same 2021 cat study found no link between fur length and grass-eating frequency, and modern pets seldom carry heavy worm loads, making the purge idea hard to test.

列举并简要评价“自我药疗”（缓解胃部不适）假说，指出数据不支持。

论证方法：引用2008年大样本调查与2021年两项猫研究，用数据反驳因果假设。
文章逻辑：先立后驳，削弱传统观点的合理性。

A third suggestion points to micronutrients—tiny amounts of B vitamins or minerals hidden in the blades. Veterinarians answer that balanced commercial diets already supply every trace element a healthy pet needs, so grazing for nutrition is unnecessary.

段落大意：讨论“机械清理”假说（排毛球、驱虫），并用研究结果削弱其说服力。

Wild relatives of our pets also consume plants, implying the behavior is instinctive rather than learned. Dr. Jamie Lovejoy therefore offers a simpler view: “Most pets probably like the taste or enjoy the feeling of chewing something fresh.” Dr. Lori Teller adds, “If your

段落大意：提出“微量元素”假说，随即以营养学共识否定其必要性。
论证方法：提出假设→专家引语→因果否定（因饮食已均衡）。
文章逻辑：快速扫描第三种解释，进一步缩小可能范围。

healthy dog or cat nibbles grass now and then, relax; only constant gorging followed by vomiting needs a vet’s attention.”

Finally, not all greenery is safe. Lilies, azaleas and certain lawn chemicals are poisonous. Owners should consult reliable lists of toxic plants and keep pesticides away from play areas.

段落大意：引入“本能/感官享受”假说，并用野生近亲行为及专家观点支持其合理性。

文章逻辑：提出最简洁解释，为全文提供相对肯定答案。

一、  基础版题目 (适合90分水平)

1. What is the main idea of the passage?

A. Pets eat grass because they feel sick.

B. Pets eat grass for many possible reasons.

C. Grass is harmful to all pets.

D. Scientists have proved why pets eat grass.

2. How many dogs showed illness before eating grass in the 2008 survey?

A. 6 %  B. 8 %  C. 9 %  D. 68 %

3. What did the 2021 study find about cats and hair balls?

A. Long-haired cats eat more grass.

B. Grass helps cats avoid hair balls.

C. Fur length had no clear effect on grass-eating.

D. All cats vomit hair balls after eating grass.

4. Why do some scientists think grass might provide vitamins?

A. Grass contains micronutrients.

B. Pets lack other foods.

C. Wild animals need vitamins.

D. Vets advise grass as medicine.

5. What should owners do if pets eat grass and vomit a lot?

A. Give more grass.

B. Change the brand of food.

C. See a vet.

D. Feed hair-ball paste.

【答案与解析】

1.B 主旨题。首段“scientists still argue”及全文列举多种可能，对应“many possible reasons”。

2.B 细节题。定位“only 8 % noticed signs of illness”。

3.C 细节题。定位“no link between fur length and grass-eating”。

4.A 细节题。定位“micronutrients…in the blades”。

5.C 细节题。定位“constant gorging…needs a vet’s attention”。

二、提高版题目 (适合130分水平)

1. The author’s primary purpose is to
   A. refute the view that grass is lethal to pets.
   B. synthesize current theories about grass-eating in pets.
   C. prove that pets eat grass solely for micronutrients.
   D. compare the digestive systems of wild and domestic carnivores.
2. Which finding most directly undermines the “upset-stomach” hypothesis?
   A. Few pets display illness before grazing.
   B. Many cats vomit after eating grass.
   C. Wild canids also ingest plant matter.
   D. Balanced diets provide all micronutrients.
3. The word “purge” in paragraph 3 most nearly means
   A. cleanse B. conceal C. generate D. digest
4. Why is the parasite-purge theory difficult to verify in modern U.S. pets?
   A. Routine deworming has reduced parasite loads.
   B. Owners rarely observe their pets’ stools.
   C. Cats are obligate carnivores.
   D. Commercial diets contain anthelmintics (驱虫药).
5. Which statement would the authors most likely endorse?
   A. All grass-eating behavior is abnormal.
   B. Occasional grazing is normal, but excessive grazing warrants investigation.
   C. Pets should be fed grass daily for extra vitamins.
   D. Artificial turf is the safest ground cover for pets.

【答案与解析】

1. B 主旨题。全文评述多种理论，未偏向单一结论。
2. A 细节题。数据显示仅8 %狗、6–9 %猫食前不适，直接冲击“因不适而吃草”。
3. A 词义题。“flush intestinal parasites”提示“purge”=cleanse。