1. My grandfather was one of the most famous musician of his time . He could play the piano like a professional

=> musicians

one of the most famous musicians: một trong số những nhạc sĩ => số nhiều
2.I hope that I won't be able to speak E fluently after this course finishes.

=> would 

I hope (that ) + I would : mong ước về tương lai
3. When Nana was only 2 year old  , she could speak mother tongue quiet well.

=> years

2 là số nhiều nên year phải thêm "s"

#NOCOPY

1. My grandfather was one of the most famous musicians in his time. He could play the piano like a professional.

2. I hope that I will be able to speak English fluently after this course finishes.

3. When Nana was only 2 years old , she could speak her mother tongue quiet well.