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Три мальчика могут вскопать за одно и то время участок земли. если будут копать два мальчика, то они вскопают этот участок за полтора часа. за сколько времени вскопают участок три мальчика вместе?
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Предмет:
Математика -
Автор:
spicy - 6 лет назад
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Ответы 0
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Еще вопросы
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I. Find the word with the same or similar meaning.
Example: research – c)
a) an experiment b) an achievement c) an exploration
1) humid
a) misty b) cool c) wet
2) icy
a) frosty b) snowy c) nasty
3) spaceship
a) space travel b) starship c) space flight
4) violent
a) weak b) strong c) terrible
5) storm
a) wind b) hurricane c) rain
II. Choose the word which best completes the sentence.
Example: I'm sure that one day the scientists will … most of medical problems.
a) take b) solve c) explore
I'm sure that one day the scientists will solve most of medical problems.
1. By exploring space we may find another … we can live on.
a) distance b) planet c) star
2. Natural disasters … cities and towns, they injure and kill people and animals.
a) break b) damage c) destroy
3. But people hope they will travel through … in huge spaceships far from the Earth.
a) space b) galaxies c) satellites
4. Scientists can now predict most weather … and warn people of possible danger in advance.
a) problems b) damage c) disasters
5. … is a sudden shaking of the ground.
a) earthquake b) flood c) drought
6. There are about 1,000 … in our Galaxy.
a) satellites b) planets c) stars
7. Sometimes the British have weather from each … all in one day.
a) climate b) season c) place
8. We don't know when men began to dream … travelling in space.
a) of b) about c) from
9. Why are you shaking … laughter? - It's better to laugh than cry.
a) like b) with c) from
10. I haven't seen them … last Halloween.
a) since b) for
III. The word in capitals above each of the following sentences can be used to form a word that fits suitably in the blank space. Fill each blank in this way.
Example: DISASTER
More than 200 people were killed during the disastrous hurricane in 1992.
1. CHANGE
Thank goodness that our weather isn't so … .
2. SUN
When we got to Spain, it was very hot and … .
3. EXPLORE
Neil Armstrong was the first … on the Moon.
4. SCIENCE
We have already discussed the most important … problems on our planet.
5. TYPE
A very violent wind is … of a tornado.
IV. Choose the correct form of the verb.
1. I … him before we met at the concert.
a) didn't see b) wasn't seeing c) hadn't seen
2. When mother came home, the children … the soup.
a) ate b) were eating c) had eaten
3. The telegram … some minutes after he had left.
a) came b) was coming c) had come
4. While we … the road I saw Victor.
a) crossed b) were crossing c) had crossed
5. When … your sister … to London?
a) did … go b) was … going c) had gone-
Предмет:
Английский язык -
Автор:
cutie piemwxn - 6 лет назад
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Ответов:
1 -
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решите уравнение
z=6-5z-
Предмет:
Математика -
Автор:
karsonexet - 6 лет назад
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Ответов:
2 -
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- Найдите значение выражения (корень из 12)/(корень из 3)
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Fe+ CuCl2=
Cu+ FeCl2
t
P + O2
= P2O5
Mg +HCl=
MgCl2 + H2↑
Al2O3+
HCl =AlCl3+ H2O
P2O5+
3H2O = H3PO4
Ba(OH)2 +HNO3=
Ba(NO3)2
+H2O
Ca +H2O
=Ca(OH)2 + H2↑
AgNO3+
KCl = KNO3+ AgCl↓
t
Fe(OH)3=
Fe2O3 +H2O
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Предмет:
Химия -
Автор:
koltongibbs - 6 лет назад
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Ответов:
3 -
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