Here are the corrections for each sentence with mistakes identified and corrected:

1. **Graham Bell is a teacher who was a school for the deaf in Massachusetts.**
**Correction:** Graham Bell is a teacher who **was** a school for the deaf in Massachusetts.
**Correct:** Graham Bell was a teacher who **taught** at a school for the deaf in Massachusetts.

2. **Telephotography, a process for sending pictures by wire, has been invented during the 1920s.**
**Correction:** Telephotography, a process for sending pictures by wire, **has been invented** during the 1920s.
**Correct:** Telephotography, a process for sending pictures by wire, **was invented** during the 1920s.

3. **The immune system is the body’s way of protecting itself against viruses.**
**Correction:** The immune system is the body’s way of protecting itself against **viruses.**
**Correct:** The immune system is the body’s way of protecting itself against **virus**.

4. **What I told her a few days ago were not the solutions to most of her problems.**
**Correction:** What I told her a few days ago **were** not the solutions to most of her problems.
**Correct:** What I told her a few days ago **was** not the solution to most of her problems.

5. **However cheap it is, the poor quality products cannot appeal to customers.**
**Correction:** However **cheap it is, the poor quality products** cannot appeal to customers.
**Correct:** However cheap it may be, **poor quality products** cannot appeal to customers.

6. **If you do not keep my secret, I would surely reveal yours.**
**Correction:** If you do not keep my secret, I **would surely reveal** yours.
**Correct:** If you do not keep my secret, I **will surely reveal** yours.

7. **Jim's grandfather left him $10,000 dollars, this was like a sum to him.**
**Correction:** Jim's grandfather left him $10,000 **dollars, this was** like a sum to him.
**Correct:** Jim's grandfather left him $10,000, **which** was like a sum to him.

8. **So Linda has been writing 5 novels on the problems teenagers have to cope with in the new world.**
**Correction:** So Linda has been writing **5 novels on** the problems teenagers **have to cope with** in the new world.
**Correct:** So Linda has been writing **novels about** the problems teenagers **must cope with** in the new world.

9. **The choice of which restaurant go to for tonight's meal is entirely your.**
**Correction:** The choice of which restaurant **go** to for tonight's meal is entirely **your**.
**Correct:** The choice of which restaurant **to go** to for tonight's meal is entirely **yours**.

10. **You mustn't hang seen my sister, for I have no sister living in this city.**
**Correction:** You mustn't **hang seen** my sister **, for** I have no sister living in this city.
**Correct:** You mustn't **have seen** my sister, for I have no sister living in this city.