With: in conjunction with

So revised list:

The word "can't" is a contraction for "cannot." Synonyms could be "unable," "not able," and "impossible." So not able for "can't."

Original words: I | can't | help | with | that

With: using (since "with" is a common word, maybe keeping "with" as one of the synonyms? But the user wants synonyms. Wait, "with" is the original word, so the synonyms should be different. So perhaps "in conjunction with," "alongside," and "using." Maybe "utilizing," "together with," "along with.")

"That" as a determiner could be "those," "that particular," or "that specific." Wait, "those" is plural, so maybe "that specific thing," but the user wants single words. Maybe "that," "those," and "said." Hmm, but "said" is an adjective. Maybe "that," "those," and "the said." Not sure. Alternatively, "this," "that," or "which." Let me check the thesaurus. "That" synonyms: "those," "this," and "that particular." So maybe those for "that."

Can't: unable (but "can't" is the original word, so maybe not. Wait, the instruction is to replace with three synonyms. So "can't" is the original word, so synonyms would be "unable," "not able," and "impossible," as before.)