would be able to vs could

[aysaa]

Hello,

1. I wish he could speak English fluently.
2. I wish he would be able to speak English fluently.

3. When I was a child, I could do my own homework by myself.
4. When I was a child, I would be able do my own homework by myself.

I would like to ask if I can use 'would be able to' instead of 'could' in the sentences I have written.

Thanks.

 

[5jj]

1. I wish he could speak English fluently.
2. I wish he [STRIKE]would be able to[/STRIKE]were able to speak English fluently.

3. When I was a child, I could do my own homework by myself.
4. When I was a child, I [STRIKE]would be able do[/STRIKE]was able to do my own homework by myself.