Here are the mistakes underlined, along with their corrections:

**10.** John **_sing_** while his friends **_dance_** **_at_** **_party._**
**Correction:** John **sings** while his friends **dance** **at** **a** **party.**

**11.** They **_study_** Spanish **_all_** year **_prepare_** **_their_** trip.
**Correction:** They **study** Spanish **all** year **to prepare** **for** their trip.

**12.** My brother **_practise_** guitar **_all_** month **_improve_** **_his_** skills.
**Correction:** My brother **practices** guitar **all** month **to improve** **his** skills.

**Exercise 16: Rewrite the following sentences using “wish”.**

1. Sarah wants to go for a hike, but she can't because of her broken leg.
**Correction:** Sarah **wishes** she could go for a hike, but she can't because of her broken leg.

2. My father doesn't have a camera. He'd like to have one.
**Correction:** My father **wishes** he had a camera.

3. Kim dreams of becoming a famous actress.
**Correction:** Kim **wishes** she could become a famous actress.

4. I want my friends to help me move to my new apartment, but they refuse.
**Correction:** I **wish** my friends would help me move to my new apartment.

5. We don't have a dishwasher. We want to have one.
**Correction:** We **wish** we had a dishwasher.

6. I'm sorry that I don't have the skills to help you with your Maths homework.
**Correction:** I **wish** I had the skills to help you with your Maths homework.

7. She wants her children to prioritise their studies and maintain good grades, but they don't.
**Correction:** She **wishes** her children would prioritise their studies and maintain good grades.

8. My sister is always on her phone. I want her to talk to me more.
**Correction:** I **wish** my sister would talk to me more instead of always being on her phone.

9. Peter works in a small town, but he would rather work in a bustling city.
**Correction:** Peter **wishes** he worked in a bustling city instead of a small town.