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long; (for a) long time
長らく連絡が取れなかった友人から電話があった。
A friend I hadn't been in contact with for a long time called me.
彼は長らくその町に住んでいる。
He has been living in that town for a long time.
その建物は長らく放置されていたが、ついに取り壊された。
The building had been left abandoned for a long time, but was finally demolished.