Find out and correct the mistakes :
1- We are going to the concert , and so do they
2- He likes to travel , and so is she
3- I will call you when I will return from my country
4- Hang borrowed the money so she could finish her education
5- I didn't understood what did he say
6- Do you know how much do they cost ?
7- Could you please tell me where is the post office?
8- There is not reason to worry
9- Bill told me that he has none friends
10- One of my friends are in the stadium