We can't use the present perfect with a finished time expression. However, if he's still helping you somehow or you are at the end of the academic year, you could use either the present perfect or the past simple. And the verb must agree with the subject - assuming he's both your professor and advisor, "who HAS helped me" (he = third-person singular).

"I can't help but thank my professor and advisor, who helped me throughout LAST year - fine "I can't help but thank my professor and advisor, who have me throughout LAST year - fine (two of them, plural) "I can't help but thank my professor and advisor, who has helped me throughout LAST year - No, plural subject must agree with verb . I guess you are copying off another thesis that wrote "I can't help but". Maybe also consider the obvious, :"I wish to thank", "I want to thank" or even the really direct "I thank". . You could consider adjectives or adverbs. most ably helped. . BTW your description of time does not strictly tell us whether they have finished helping. . Just a native speaker of English and a reader of theses.

Hello! In this case - "who have helped me throughout the past year".

Simple past is used if an action happened in the past and finished. I walked, I ate- they happen, they are over Present perfect- I have eatne, I have gone... implies that the activity started in the past, continued on and is still possibly going on up to now. Past perfect- 'I had gone to Europe twice', is something that started int he past, went on, then ended in the past. So, is the advisor still helping you? then 'Have helped me throguhout the past year'. Did they help you one time and stop? 'Helped me'. Did they help you last year but aren't helping you now? then 'Had helped me through the past year.

Gabriel Either way is ok I think. Personally I'd say 'thoughout the past year'. Duane