what are the differences between those two sentences besides past and present tense?
1. i can do it
2. i could do it
same goes to
3. i would tell you
4. i will tell you
With 3 & 4 the difference is that in 4 you will get the information and in 3 you won't unless certain things happen, like your doing something or my having permission to tell, etc.
There could be many differences btween the first two. 'Can' expresses' a real ability, while 'could' is less certain (unless wse are talking about a past ability). Let's take a situation- you need help. Here. if I want to sound helpful, I'll use the present to sound positive and helpful. However, if I'm volunteering for something where other people may want the same thing, I would use 'could' to allow others room to make their offers.
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