text: (1)i am a secretary for five years.  (2) i have seen him yesterday. (3)she's liked him since six months.? what the mistake is in above sentence. pls give me the correct tense form. (1)i have been a secretary for five years.   'am' is present tense and 'for five years' is a past tense duration  (2) i saw him yesterday.  'have seen' is used for a present statements about the past as in 'i have seen a grown man cry' whereas 'saw' directly relates to the past  (3) she's liked him for six months.  'since' refers to a starting point in the past whereas 'for' in this case refers to the duration 'six months'