1.when i went theree he was watching television since a long time.
When i went there he had been watching television for a long time

2.he said that he was a student of the college for the last two years.
He said that he had been a student of the college since the last two years.

3.I saw him in the morning of twele december.
I saw him in the morning of twelfth December

4.How long do you know him.
Since how long do you know him?

5.as every body knows that we pakistanies have not been able to manage our affairs successfully.
As everybody knows that we, Pakistanis have not been able to manage our affairs successfully.

6.i would be grateful if you kindly help
I would be grateful if you kindly help me.

7. i was informed by the security guard the manager left five minuts ago.
I was informed by the security guard that the manager had left five minutes ago.

8.hardly he passed the examination he recieved a good job offer.
Hardly had he passed the examination when he received a good job offer.

9.can you tell me that how can i learn english quickly.
Can you tell me how can i learn english quickly?

10.when i reached at the station he was waiting for me at the platform the last two hours.
When i reached the station he had been waiting for me at the platform since the last two hours.
--------------------------------------------------------------------------Do Comment to emend it, if possible.