Complete the sentences using must or can't and the correct tense of the infinitive. 1 I'm certain Adam sent you an email. Adam
2 I don't think Tina left the door unlocked.
Tina
3 I'm sure Keith paid the bill.
Keith
4 I don't think they are staying with Paul. He's away.
They ...
5 I don't think Jeff forgot their wedding anniversary.
Jeff
6 I'm certain Julie is waiting for us at the reception.
Julie
7. I am sure Mary went to India for her gap year.
Mary
8 I'm sure Steven enjoyed living with his host family in Mexico.
Steven
9 I'm sure she's had cosmetic surgery. She
10 I'm certain they grow their own food. They
11 I don't think Jenny has won a scholarship.
Jenny

All the energy we receive , ultimately comes either from the sun or from the ground.
The sun heats our planet , and supplies required for plant growth light . And in the distant past the sun in the same way our planet has implemented energy. His energy is transformed into plants , animal life supported . Due to this we get today coal, oil and natural gas - the so-called fossil fuel resources on which our civilization depends significantly .
The only alternative energy source that is in the earth - the atoms of certain elements that formed long before the advent of the solar system. They are now in the crust * .
* Uranium contained in the earth's crust , formed about 6.5 billion years ago, and its concentration is on average 0.14 %. Heat from the radioactive decay of uranium today manages the processes of convection in the Earth's crust.
The amount of energy per unit mass of an atom depends upon the size of atom minimum amount of energy per unit mass of the atoms contained in the medium size ( such as carbon and oxygen) , while increasing the amount of the atoms contained in the small ( such as hydrogen ) or large ( such as uranium) . Energy can therefore be obtained either by joining smaller atoms atoms in average sizes (synthesis ) or by dividing the larger atom to medium size ( splitting). Development of fusion energy and humanity splitting energy is one of the most important achievements in the history .

1 Beijing has changed so much in the last few years that it’s almost irrecognisable. (RECOGNISE).
2 The number of cars in the world (WORLD) is about a billion and is increasing all the time.
3 The new maglev trains run on a completely different (DIFFER) system from ordinary trains.
4 Living in a foreign country really does broaden (BROAD) your horizons.
5 I can’t find a (DIRECT) flight from London to Delhi so I’ve booked one that
changes in Frankfurt.
6 All passengers must complete a visa form upon arrival (ARRIVE) at Singapore airport.
7 You can still see old milestones by the side of the road in England, showing the distance (DISTANT) to the nearest town.
8 The Museum of Transport has a full-sized jet plane next to the entrance (ENTER).