There's a mistake in each sentence, underline and correct it

V. There's a mistake in each sentence, underline and correct it: 
1. Last Sunday we went to the concert performing by the most famous singers.………………………………
2. We always encouraged to discuss our problem.                    ………………………………
3. He picked up a wallet and finds a ticket inside.                    ………………………………
4. I haven't written to my friend since the last two weeks.            ……………………………….

VI. Rewrite the following sentences.
1 James is sorry that he is not hard - working. 
James wishes………………………………………………………………………………………….………….
2 It's a pity Tom is sick today.    
If only…………………………………………………………………………………………………….………………..    
3 Are you ever sorry that you are poor? 
Have you……………………………………………………………………………………………………………….
4 They are sorry that they don't correspond very often. 
They……………………………………………………………………………………………………………………..
5 The reason why Mr. Nam was absent is a mystery. 
Until now nobody…………………………………………………………………………………………………….