What is the defference bettween the following two sentences
1- I have been working here for two years
2- I have worked here for two years
also in the following sentence why (want) is in the past
- I told her father that I wanted to marry her
(1) and (2) are quite similar in intent, but the continuous tense emphasizes the ongoing activity of working, while the simple tense states the simple fact of the event. Continuous often shows the speaker's interest or involvement in the topic.
In the third sentence, the verb of reported speech is normally consistent with the time of the report ('told'), not with the time of the original speech. But in your sentence, for instance, if the situation still holds true-- if you still want to marry her-- then the present simple is equally acceptable.