Could
Could berfungsi untuk menunjukkan kemampuan yang masih belum bisa dipastikan. Selain itu, could juga berfungsi mengajukan permohonan dengan lebih sopan.
Example:
I think I could do it in five hours
Maybe she could finish that better than you, so give her a chance
Could you please look after Chloe for a while?
Should
Should berfungsi menunjukkan sesuatu yang seharusnya dilakukan, baik di masa lalu mau pun di masa depan. Should juga bisa digunakan untuk memberikan saran pada orang lain.
Example:
I should go now, Mike is waiting for me
You should go to school earlier, or you’re going to get another punishment after this
She should do it immediately or her mother will kill her
Would
Would berfungsi untuk menunjukkan sesuatu yang akan dilakukan, tapi belum pasti. Selain itu would juga bisa digunakan untuk meminta/menawarkan sesuatu dengan sopan.
Example:
I would do that sooner or later
I don’t know if I could, but I would do that if there’s a chance
Would you like some additional sugar on your coffee, Sir?
