Can someone help me to understand why we use "Could' in this sentence instead of 'can'.

"GST could make some products cost less" vs "GST can make some products cost less"


  • 3
    "Could" is used to indicate a possibility. So GSTmay very well make some products cost less, but it may also not.
    – MorganFR
    Commented Aug 3, 2016 at 9:01
  • en.wikipedia.org/wiki/English_subjunctive: "would, should, could and might can in some contexts be regarded as past subjunctives of will, shall, can and may respectively. (They may also be described simply as the past forms of the latter modals, or as modals or auxiliaries in their own right.)"
    – phoog
    Commented Aug 3, 2016 at 9:03
  • can we not use "Can" to refer the 'Possibility'?
    – santhosha
    Commented Aug 3, 2016 at 9:22
  • I'd argue that 'can' strengthens the possibility, without actual introducing a guarantee. 'I can attend the meeting' - I intend to appear if confirmed, or 'I could attend the meeting' - you are going to have to tell me you really want me there.
    – Cato
    Commented Aug 3, 2016 at 10:28

1 Answer 1


The difference seems to be in whether positivity or negativity is being implied. So a shop worker will often say 'Yes I can provide you with free box for that'. They might also say 'I could provide you with a box, but it isn't quite suitable.'

So 'could' seems to imply to me that they aren't going to carry out the act.

In the future you might find yourself saying.

'GST could have made some products cost less' (but they never did that)

OR in the case of your second (more positive sentence)

'GST have made some products cost less' (they did do that)

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