Đề ôn thi Đề thi vào lớp 10 Trường THPT Chuyên KHXH môn Tiếng Anh - Mã đề KHXH-93

Modern health technology has made everyday medical devices safer and more convenient than ever before. A perfect example is the digital thermometer, now common in homes and hospitals. Unlike older glass thermometers that used mercury, today's electronic versions provide a fast reading without the risk of toxic materials. They are generally (35) __________ and easier to read, thanks to their clear digital screens. The technology inside these devices is surprisingly straightforward, centered around a special electronic component.

At the heart of every digital thermometer is a sensor called a thermistor. The name comes from a combination of the words 'thermal' and 'resistor'. A thermistor is a type of resistor whose electrical resistance changes significantly with temperature. The entire function of the thermometer (36) __________ this predictable relationship. The material used to make the thermistor is a special semiconductor, engineered to be highly sensitive to even small fluctuations in heat.

When you place the tip of the thermometer under your tongue or arm, the heat from your body transfers to the thermistor. As the thermistor's temperature rises, its electrical resistance decreases, (37) __________ then alters the flow of electricity through it. A tiny computer inside the device, called a microcontroller, constantly monitors this electrical resistance. Once the resistance stops changing, the microcontroller knows that the sensor has reached the same temperature as the body, and it (38) __________ then calculate the final reading.

The microcontroller does not directly measure temperature. Instead, it measures the electrical resistance and then uses a pre-programmed mathematical formula to convert that resistance value into a temperature reading, such as Celsius or Fahrenheit. To do this (39) __________, the microcontroller must (40) __________ a calculation based on the thermistor's known properties. (41) __________ the process take more than a minute. The final calculated temperature is then sent to a small liquid-crystal display (LCD), which shows the numbers we can easily read.

(42) __________, the digital thermometer works by translating a physical property—heat—into an electrical signal, which is then converted into a digital number. This clever, multi-step process is what allows for the fast, safe, and accurate temperature measurements that are so important for monitoring our health. It’s a simple but brilliant piece of everyday health technology.

Dengue fever is a viral infection that has become a significant public health concern in tropical and subtropical regions, including Vietnam. Transmitted by the bite of an infected Aedes mosquito, the disease can affect anyone, but its prevention is something in which everyone, including teenagers, can play a crucial role. While there is no specific medicine to cure dengue, understanding how it spreads and taking proactive steps are the best defenses to protect ourselves and our families.

The symptoms of dengue typically begin four to ten days after being bitten by an infected mosquito. A person with dengue often experiences a high fever, severe headache, pain behind the eyes, muscle and joint pains, and a skin rash. While most people recover within a week or so, some cases can develop into a more severe form known as Dengue Hemorrhagic Fever. This condition can be life-threatening and requires immediate medical attention, which is why recognizing the initial symptoms is so important.

The primary carrier of dengue, the Aedes mosquito, is easily identifiable by the white markings on its legs. Unlike other mosquitoes that are most active at night, the Aedes mosquito typically bites during the daytime. It breeds in small pools of clean, standing water often found around homes. Flower pots, old tires, discarded containers, and even blocked roof gutters can become potential breeding grounds. These locations are often overlooked. They can be found both inside and outside the home, making constant vigilance a necessity.

The most effective way to prevent dengue is to eliminate mosquito breeding sites. This is a simple but powerful action that everyone can participate in. Regularly, you should empty water from flower pot saucers and other containers. Large water storage tanks should be tightly covered to prevent mosquitoes from laying eggs in them. It is also important to dispose of any rubbish, such as old bottles, cans, and tires, that can collect rainwater. By keeping our living environment clean and free of standing water, we disrupt the mosquito's life cycle.

In addition to controlling mosquito populations, personal protection is also vital. When outdoors, especially during peak biting hours in the early morning and late afternoon, using an effective mosquito repellent is highly recommended. Wearing light-colored, long-sleeved shirts and long pants can also provide a physical barrier against bites. At home, installing screens on windows and doors can prevent mosquitoes from entering. These simple habits significantly reduce the risk of being bitten.

In conclusion, fighting dengue fever is a shared responsibility. It does not require complex technology or expensive resources. Instead, it relies on community awareness and consistent, simple actions taken by individuals and families. By eliminating breeding grounds and protecting ourselves from bites, we can create a safer community for everyone.