Help please
Choose one of the options to fill in the gaps.
(Выберите один из вариантов, чтобы заполнить пробелы.)
1. At present Canada ___ a high-speed rail system. *
have not
does not have
do not have
is not having
2. By the 17th century, temperatures in the Northern Hemisphere ___ by half a degree Celsius compared with medieval times. *
was falling
fell
has fallen
had fallen
3. Recently, a scientist at the University of Illinois ___ a tiny device that can measure a wearer’s blood flow and wirelessly send that information to a computer. *
has invented
invent
are inventing
have invented
4. Computers ___ such games as chess already. *
have mastered
are mastered
has mastered
master
5. The human brain ___ a built-in talent for working out depth from flat images. *
have
is having
had
has
6. He ___ his mobile phone for already 3 hours. *
has charged
has been charging
is charging
was charging
7. They ___ the football match when the phone rang. *
discussed
were discussed
were discussing
are discussing
8. He gave his reasons for what ___. *
was happened
had happened
has happened
happened
9. She ___ till you come. *
was working
is working
will be working
worked
10. The abstract ___ translated by the evening. *
will be
will
will be being
will have been
11. I suspect that ___ an error in these calculations. *
it is
there is
is
be
12. The problem which ___ now is very urgent. *
discusses
is discussing
is being discussed
discussed
13. Scientists ___ the existence of neutron stars as long ago as 1934. *
have predicted
predicted
has predicted
had predicted
14. A man was stopped by the policeman when he ___ to cross the street at the red light. *
was go
was going
had been going
is going
15. Today, nuclear power plants ___ in 31 of 196 countries. *
are operate
operates
operate
is operating
16. Valentine’s Day ___ on February 14. *
is celebrated
is being celebrated
celebrates
has celebrated
17. The new aircraft ___ by the end of the next year. *
will have building
will build
will have been built
will be building
18. Peter Higgs ___ the existence of the particle nearly five decades ago. *
has proposed
has been proposed
was proposed
proposed
19. The Arctic ecological problems ___ a lot of attention right now. *
receives
are receiving
receive
receiving
20. The footballers ___ the first period when the thunderstorm began. *
played
were played
were playing
were being played
21. The room was empty, everyone ___ a few minutes before. *
left
has left
was left
had left
22. This film ___ tomorrow. *
shows
will show
will be shown
will showing
23. Mr. Smith ___ to the Police. *
not rang
do not ring
did not rang
did not ring
24. What ___ you doing from 7 till 9 yesterday? *
had
were
did
have
25. I have never ___ such a beautiful flower. *
see
seeing
seen
saw