Дополните диалог:
Helen: Professor, there is some new equipment in the lab, isn’t there?
Professor: 1_______.
Helen: 2_______ what this thing is called?
Professor: A laser. It is known as a laser.
Helen: What is it used for?
Professor: It’s used for producing a very powerful beam of light.
Helen: What are these?
Professor: 3_______, they are known as pressure gauges. What are they used for? 4_______?
Helen: They are used for measuring pressure, aren’t they?
Professor: Right you are. And this type of gauges is used for measuring low pressures.