Ok. Thanks. I have already a problem with the correct translation from English to German.. "How do you know her?" = "wie kennst du Sie?" ... in my opinion.. I thought so.. and this is my problem, why I did not understand the meaning.. :-) ..
Learning Dutch from English, although my English is not perfect, makes the lessons not easier :-)
How do you know her? implies that she is a current acquaintance. How did you know her? refers to an acquaintance from the past: you might even be asking the question at her funeral. Compare also: How did you get to know her? which could refer to a current or past acquaintance.
Well, the sentence starts with an interrogative pronoun (hoe or 'how' in English). In Dutch, the verb comes second in these types of sentences, so Hoe kent are the first two words. These are followed by the subject (u) and the object haar (in this order). This forms: Hoe kent u haar?