Дополните диалог: Teacher: Hello my friends. Today I’m going to show you an operating 1_______. Ivan...: ответ на тест 867584 - Английский язык

Дополните диалог:
Teacher: Hello, my friends. Today, I’m going to show you an operating 1_______.
Ivan: That’s great! By the way, what does the word “laser” mean?
Teacher: 2_______. Looking at the operating laser one can see it producing a very powerful beam of light.
Ivan: When did the first lasers appear, I wonder?
Teacher: As far as I know, in the 1960s. Yet, we hear of their having numerous applications. 3_______.
Ivan: And how do lasers work?
Teacher: Their work is based on the principle of amplifying the light of a certain wavelength in the resonator cavity.
Ivan: I’m rather interested in making experiments with laser beams.
Teacher: Then let’s try to make one. But be very careful. Lasers can be very 4_______.
Ivan: Why are they dangerous?
Teacher: Well, they produce a very powerful beam of light and if treated in the wrong way it can hurt or even kill you.
Ivan: Oh, I’m pretty scared.
Teacher: Don’t worry. If you follow all the safety instructions nothing will happen to you.