Decide whether to use the definite article the or not

1.	Last year we visited _-_ Ukraine.
2.	_-_ mount Everest is the highest mountain on _the_ planet.
3.	_the_ river Dniper is _the_ biggest river in the region.
4.	_-_ most children dislike it.
5.	_the_ summer of 2010 was hot and dry.
6.	_-_ smog is a problem in _-_ most big cities.
7.	Our children go to _-_ school by bus.
8.	_-_ apples are good for people.
9.	In our country _-_ milk is more expensive than _-_ beer.
10.	We had a very nice meal in that restaurant. _the_ food was really good.
11.	They got married two years ago but _the_ marriage wasn't successful.
12.	I know someone who wrote a book about _the_ life of V. Lenin.
13.	_-_ cycling is my favourite sport but I also like _-_ swimming.
14.	Do you know _the_ family who lives next house?
15.	Are you interested in _-_ photography or _-_ drawing?