13. Match the adjectives and their opposites
-
1
coherent
a
unusual
2h
complicated
b
distant
3
Conventional(обычный)
c
connected
4g
dormant
d
total
5i
dual
e
unclear
6c
isolated
f
discontinued
7b
neighbouring
g
active
8a
ongoing
h
simple
9d
partial
i
single
14. Describe how a laser works, using the words from the list below in their correct form. There are 2 words that you don`t need to use.
To concentrate to emit fully to absorb atom photon partial back and forth ruby crystal coherent
The power source is located below the (1) ruby crystal and makes the tube flash on and off. Every time the tube flashes, the flashes inject energy into the crystal in the form of (2) photon, which are particles of light.
In the first stage, (3) atoms in the ruby crystal (4)absorb the energy from the light tube. When the atom absorbs a photon, it becomes more excited for a few milliseconds [ˈmɪl.ɪˌsek.ənd], and then returns to its original state and (5) emit a new photon.
Next, the photons travel at the speed of light (6 back and forth inside the ruby crystal. At the far end of the tube, a (7) partial mirror reflects most of the photons, about 99% of them, back into the crystal, but lets a small number, about 1%, escape from the machine.
Finally, these escaping photons form a very (8) consentrate beam of powerful laser light.
Grammar
Revision
https://www.youtube.com/watch?v=fVlgzuhBi-I
Watch the video and be ready to discuss the examples mentioned in it to your group mates:
What is the difference between active and passive structures in the sentence? Give a couple of examples from the video.
What does he call ‘past Infinitive’?
The full Infinitive (=the Infinitive with ‘to’= the ‘to’ Infinitive)/ V-ing form
The -ing form is used:
as a noun, mostly the name of a process.
e.g. Smoking is dangerous. Walking is a good exercise. My hobby is reading memoirs.
after: love, like, dislike, hate, enjoy, prefer (likes and dislikes)
e.g. I love going to the theatre. I hate being laughed at.
after: start, begin, keep, go on, stop, finish, give up. (verbs denoting start, continuation and completion)
e.g. He started doing his homework at 5:00 pm. They went on adjusting the equipment.
after “go” for sports and physical activities.
e.g. She went skiing last Sunday. She is ready to go shopping at any moment.
after certain verbs (avoid, admit, confess, deny, look forward to, mind, object to, prefer, regret, risk, spend, suggest, etc.).
e.g. I don't mind helping you with the dishes.
after the expressions: I'm busy, it's no use, it's (no) good, it's worth, what's the use of, be used to, there's no point (in), can’t help, can’t stand.
e.g. It's worth seeing that film. It was no use spending so much time on the problem. We couldn’t help being involved into the discussion. What is the use of doing it over and over?
after prepositions.
He left without taking his coat. He was accused of stealing.
The to-Infinitive is used:
to express purpose.
e.g. He went to buy some bread. She entered the University to become an engineer.
after would like / would love / prefer.
e.g. I would like to visit him. I'd love to see you tonight. I prefer to stay in the town.
after certain adjectives (angry, glad, happy, sorry, pleased, annoyed, etc.).
e.g. I'm glad to see you here. Tom was happy to see them.
with too or enough.
e.g. He's too old to drive. She's clever enough to understand it.
after certain verbs (advise, agree, decide, expect, forget, offer, promise, refuse, want, etc.)
e.g. I hope to meet him again. He decided to quit. We agreed to start our business.
after question words (where, how, what, who, which). Why is not used with to-infinitive.
e.g. I don't know what to do. They forgot where to turn right. We didn’t know how to switch on the device.
Note: Some verbs can take the to-infinitive (a full infinitive) or the -ing form with no difference in meaning. These verbs are: begin, hate, like, love, prefer, start, regret, intend, forget, propose, etc.
e.g. He likes to watch / watching the birds. She regretted to have mentioned / mentioning that name. We love having / to have a lot of dogs around.
