Where (you/be)? I (not/see) you for ages.

The sentence describes a situation that started in the past and continues to the present, indicating the use of the present perfect tense. The first blank requires the present perfect form of 'to be' for 'you', which is 'have you been'. The second blank requires the present perfect negative form of 'to see' for 'I', which is 'haven't seen'.

Answer: Where have you been? I haven't seen you for ages.