Неопределенный артикль не ставим перед существительным во множественном числе, потому !

Потому что А это аналог ONE

1).
1The Town Mouse lives in a town.
2 She is white.
3 The Town Mouse likes to play computer games.
4 She can dance well.

2).
    In summer we can swim!
    In winter we can skate!
    At any season we can play computer games! 
3)
- Do you like autumn?  -- No, I don,t like autumn.
- Do you play tennis in summer?  --Yes, we do. We play tennis in summer.
- Can you ski and skate?    --Yes, I can. I can ski and skate.
- Has he got a nice bike? --Yes, he has. He has got a nice bike.
- Does she like spring? --Yes, she does. She likes spring.

1).
1The Town Mouse lives in a town.
2 She is white.
3 The Town Mouse likes to play computer games.
4 She can dance well.

2).
    In summer we can swim!
    In winter we can skate!
    At any season we can play computer games! 
3)
- Do you like autumn?  -- No, I don,t like autumn.
- Do you play tennis in summer?  --Yes, we do. We play tennis in summer.
- Can you ski and skate?    --Yes, I can. I can ski and skate.
- Has he got a nice bike? --Yes, he has. He has got a nice bike.
- Does she like spring? --Yes, she does. She likes spring.