1. How many hour a day do you watch television?
=> How many hours a day do you watch television?

2. Children shouldn't spend too much time to watch television.
 => Children shouldn't spend too much time watching television.

3. Many people work hardly every day to produce TV programmes.
=>Many people work hard every day to produce TV programmes.

4. The 7 o'clock news tell people what is happening in the world.
=>The 7 o'clock news tells people what is happening in the world.