Does the word "saw" contain more than one morpheme? If so, how is this possible in such a short word? Are there any other words of this length that have multiple morphemes? I have just started studying linguistics and morphology, so I am probably just missing something, but I don't understand how it could be more than one.
One analysis is 2: see + the -ed past tense inflection, realized as 'saw.' I think Steven Pinker's book Words and Rules argues that this is a single morpheme. But if you are having trouble in general counting morphemes, be sure you get clear on the 8 inflections we have in English and can recognize derivational morphemes. About short words with multiple morphemes, start wtih those with more 'regular' forms, like ants (noun ant + -s plural infl) or hoed (hoe + -ed past tense infl). Those are pretty short! Then note that sometimes the form of the resulting combination isn't regular: cut + -ed past tense infl --> cut; do + -ed past tense inf --> did); ox + -s plural inf --> oxen; have + -s 3rd-person-singular present tense marker --> has. Hope that helps.