How long have you been in Sydney?Since last Wednesday .I ___

How long have you been in Sydney?Since last Wednesday .I ___ --how long have you been here in sydney?--____last wednesday how　long　have you been in China?——Since last Wednesday 啥意思 ——（）have you been in China?——Since last Wednesday I ___ you____ in London .how long have you been here? it's been a long time since I------.How are you?A.had last s 几道英语题求解和理由——How long have you been here in Sydney?——______la how have you been since l saw you last How long have you been in China? How long have you been in China How long have you been for china与How long have you been in c I have been in CZ since last year.这话对么?been in后可加since吗