I think that "would" would be better than "could" there. And a period/full stop is needed at the end.
Student or Learner
Please check this sentence "I bought some eggs put them into fridge so that they could get cold"
I think that this part needs a little work:
I bought some eggs put them into fridge
And "the fridge."
"Refrigerate" is nearly always used on the instructions on a packet/tin/bottle of food.
"Refrigerate after opening and use within four days."
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.