"That" can be replaced with "this", "the", "the one". But "this" is a synonym in some contexts. Alternatively, "that", "which", "the". Not sure if all are acceptable. Maybe "that", "those", "the". Wait, "those" is plural. Alternatively, "that", "the same", "the". Hmm.
For "can't": cannot, unable, not able
Putting it all together: I can't|cannot|unable assistusingthat But need to check each has three options. For "can't", "can't", "cannot", "unable"
"That" – "this", "the", "that particular".
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