Definite articles exercises

Definite articles exercises. Choose the right artilces a, or the. If it isn't necessary to use either a or the, then choose x which stands for zero article.
1 It was the first country to send a man into space.
2 Did you see the film on television or at cinema?
3 It was beautiful day. The sun shone brightly in sky.
4 I've invited Tom to dinner next Wednesday.
5 What is highest mountain in the world?
6 We don't go to theatre very much these days.
7 It was long voyage. We were at sea for four weeks.
8 I prefer swimming in sea to swimming in pools.
9 Can you turn television down, please? It's a bit loud.
10 'Is he a rich man?' 'Yes, he is richest man I’ve ever met.