Задание

Прочитай приведённые ниже тексты. Преобразуй, если необходимо, слова, напечатанные заглавными буквами в скобках, обозначенных номерами 19–24, так, чтобы они грамматически соответствовали содержанию текстов. Заполни пропуски полученными словами. Каждый пропуск соответствует отдельному заданию из группы 19–24.

Why do veins look blue?

Your blood 19.___________(GET) its colouration from red blood cells. So, why do veins in your arms appear to be blue? The answer lies in the fact that different colours of light have different wavelengths, so they are absorbed and reflected differently when they hit our skin. If you shine white light — a mixture of all the different wavelengths — onto your arm, the red light will be absorbed and the blue light will be reflected. This means that the light returning to your eyes will contain more blue than red wavelengths.

Medics sometimes make use of this phenomenon to help 20.___________(THEY) locate a vein to administer an injection. Similarly, nightclubs use blue lights in the toilets to discourage intravenous drug use by 21.___________(MAKE) it hard to see veins through the skin.

Measles

The history of measles, like many other diseases, is unknown. However, mankind has known it since ancient times. One of the 22.___________(ONE) symptoms of measles was described by an Arab scientist Al Razi in the 9th century.

Before the vaccine, measles affected almost all of the population. Nearly all 23.___________(CHILD) got measles by age 15.

In 1954, John F. Enders and Dr Thomas C. Peebles succeeded in isolating the measles virus in blood and creating a measles vaccine. In 1963, they licensed a vaccine. In 1968, an improved measles vaccine, developed by Maurice Hilleman and colleagues, began 24.___________(DISTRIBUTE).

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