Open the brackets. Mind the correct word order of these adverbs

Choose the sentences in the Perfect Tenses and translate them.

Translate and memorize the following words.

UNIT II METALS

Now you can speak about most elements of the Periodic Table. Characterize any substance you want except for those ones described above.

Grammar: ThePerfect Tenses

The use of since

Text: Rare Metals

conduct	luster	primary
fall into	hardness	rare
appear	consequence	plentiful
manufacture	bond	several
purify	alloy	refractory
distribute	ore	rare-earth
mine	refine	ductile

2. Define the parts of speech and translate:

conduct – conductivity; luster – lustrous; primary – primarily; consequence – consequent – consequently; stable – unstable; purify – purity – impurity – purification – pure.

3. Find the pairs of antonyms:

dull, refractory, unite, hard, appear, plentiful, pure, conductive, lustrous, fall into, soft, non-conductive, ignitable, disappear, rare, impure.

4. Find the pairs of synonyms:

several, due to, plentiful, purify, produce, fundamental, refine, manufacture, some, thanks to, common, primary.

Study and remember the following chart:

	Perfect Active   have + P II	Perfect Passive   have + been + P II
Present	He has received a letter.   Он получил письмо.	The letter has been received. Письмо получено.
Past	He had received a letter by the evening yesterday.   Он получил письмо вчера к вечеру.	The letter had been received by the evening yesterday.   Письмо было получено вчера к вечеру.
Future	He will have received a letter by the evening received by the evening tomorrow. Он получит письмо завтра к вечеру.	The letter will have been received by the evening tomorrow.   Письмо будет получено завтра к вечеру.

5. Form the Present Perfect forms of the following verbs:

Model: to give – have/has given

to be asked - have/has been asked

to begin, to classify, to hear, to state, to learn, to refine, to discover, to find, to found, to mention.

1. They have carried out the series of experiments successfully. 2. The plan has to be carried out. 3. The group will have carried out all the experiment by the end of the week. 4. The plan has been carried out. 5. The experiment is being carried out. 6. The synthesis has been carrying out for six hours. 7. The plan had been carried out by the 1st of November. 8. We have to carry out the series of experiments for a month.

1. They have completed their work (already). 2. The scientists haven’t classified this metal under a definite group (yet). 3. You have learnt the news (certainly). 4. The bell has gone (just). 5 Have the technologists tested these samples (already)? 5. You have heard of some platinum metals (probably). 6. The refining has been carried out (just).

8. Translate the following sentences into Russian:

Note: since - с тех пор, как; со времени

- так как, поскольку

1. Since we know all the properties of the substance, we can use it in our experiment. 2. Many interesting investigations have been done since the foundation of this research la­boratory at our plant. 3. Helium belongs to the same group as argon since it does not combine with other elements. 4. I have not carried out any experiments in the laboratory since I graduated from the Institute. 5. We couldn't finish our work since we had no necessary devices. 6. Since the kinetics of the reaction was studied at room temperature, the results were good. 7. This element has been known since the 19 ^th century.

9. Ask whether these things have already done.

Model: We have mixed these substances.

Have you already mixed these substances?

The report has been sent.

Has the report already been sent?

1. They have heated the solution. 2. The metal has been extracted from the ore. 3. The results have been analyzed. 4. We have broken down the oxide into two elements by heating. 5. I’ve defined these substances. 6. Everything had been done before he came.

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