Could you tell, please, the difference between ''IN'' and ''WITHIN''?
In French, we use the same word for both. What difference English makes between them. In what case can we use IN but not WITHIN and vice versa. Thanks.

Question

Answer

(c) >I'll finish the work in a couple of days

That suggests that the work will not be completed in anything less than a couple of days. At least a few days will pass before the work is completed.

>I'll finish the work within a couple of days

That suggests that the work might be completed sooner; the worst possible case is that it will take a couple of days to complete.

Answer

1. ‘In’ and ‘within’ are both prepositions that refer to spatial or a logical relationship between two or more subjects in a sentence.

2. ‘In’ is specifically defined as being inside,  while ‘within’ implies being inside of a given set of parameters relative to the object it’s linking to and not actually inside of it.