more verb tenses anyone?

[spank]

I'm looking for a tense that is equivalent to English's

"has/have been doing.."
Now, i know there is ＋ている、＋ていた　＝am doing, was/were doing.
Some may say there is no distinction between "was" and "has been" but...

I would like to say in Japanese things like...

"Oh, how long have you been studying English?"
"You have been playing piano for ages now."



I think I came across this structure before, but I am sorta silly and forgot what it was.:p

[skrhgh3b]

Oh, how long have you been studying English?
あ、どのくらい英語を勉強していますか？
You have been playing piano for ages now.
長いことピアノを弾いてきましたね。