Phonetics and the IPA 8, Exercise 3: can

Weak form    /kən/  used when unstressed in the middle of a phrase:
                    "I can swim"  -> /aɪ kən swɪm/ (broad, my transcription)
Strong form  /kæn/  used when stressed, phrase-final, or cited in isolation:
                    "Yes, I can."  -> /jɛs aɪ kæn/ (broad, my transcription)

Source for the two forms and the conditions: Wikipedia, "Weak and strong
forms in English". The two example sentences and their transcriptions are
my own illustrations; accent details (GA vs RP symbols) are left aside here.