Diseases are a natural part of life on earth. If there were no diseases, the population would grow too quickly, and there would not be enough food or other resources, so in a way, diseases are natural ways of keeping the Earth in balance. But sometimes they spread very quickly and kill large numbers of people. For example, in 1918, an outbreak of the flu spread across the world, killing over 25 million people in only six months. Such terrible outbreaks of a disease are called pandemics.

Pandemics happen when a disease changes in a way that our bodies are not prepared to fight. In 1918, a new type of flu virus appeared. Our bodies had no way to fight this new flu virus, and so it spread very quickly and killed large numbers of people. While there have been many different pandemic diseases throughout history, all of them have a new thing in common.

First, all pandemic diseases spread from one person to another very easily.

Second, while they may kill many people, they generally do not kill people very quickly. A good example of this would be the Marburg virus. The Marburg virus is an extremely infectious disease. In addition, it is deadly. About 70 -80% of all people who get the Marburg virus died from the disease. However, the Marburg virus has not become a pandemic because most people die within three days of getting the disease. This means that the virus does not have enough time to spread a large number of people. The flu virus of 1918, on the other hand, generally took about a week to ten days to kill its victims, so it had more time to spread.

While we may never be able to completely stop pandemics, we can make them less common. Doctors carefully monitor new diseases that they fear could become pandemics. For example, in 2002, and 2003, doctors carefully watched SARS. Their health warnings may have prevented SARS from becoming a pandemic.

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Question 22. Diseases are natural ways of _____________.
A. reducing population​​​ B. keeping the Earth in balance
C. developing the population​​​ D. rising the animals

Question 23. The word "it" in the paragraph 2 refers to ______________ .
​A. flu virus​ B. disease​ C. pandemics​ D. bodies

Question 24. This passage is mainly about ____
​A. pandemic diseases throughout history
​B. how to prevent pandemic diseases
​C. pandemic diseases
​D. why pandemics happen

Question 25. According to the passage, all of the following are true of the 1918 flu pandemic EXCEPT that ________ .
​A. it involved a new kind of flu virus
​B. it killed over 25 million people
​C. it was the last pandemic in history
​D. it took a little over a week to kill its victims

Question 26. Base on the information in the passage, the term “pandemics” can be explain as ______________.
​A. diseases that spread quickly large a numbers of people
​B. New diseases like SARS  or the Murburg virus
​C. deadly kind of flue
​D. diseases with no cure

$22.$ $B$

$-$ Câu đầu tiên của bài: " ... so in a way, diseases are natural ways of keeping the Earth in balance".

- " ...  vì vậy, theo một cách nào đó, bệnh dịch là một cách tự nhiên để giữ cho Trái đất luôn ở trạng thái cân bằng".

$23.$ $A$

- Từ "it" trong đoạn $2$ đề cập đến "flu virus".

- "Our bodies had no way to fight this new flu virus, and so it spread very quickly and killed large numbers of people".

- "Cơ thể con người không thể chống lại virus này, nên nó lan rộng nhanh chóng và giết rất nhiều người".

$24.$ $C$

- Nội dung chính của đoạn văn là về dịch bệnh.

$25.$ $C$

- Việc "nó là đại dịch cuối cùng trong lịch sử" là sai vì không có dẫn chứng nào như thế trong bài.

$26.$ $C$

- "Dựa vào thông tin trong bài, thuật ngữ “pandemics” có thể được giải thích là loại cúm chết người".