いつまでも の訳語→ always continually continue endlessly eternal forever indelibly interminably long remain still
しきりに の訳語→ bitterly busily conjecture copiously desperately eagerly earnestly fluently frequently furiously hard imperiously insistently intently keep much often rapid steadfastly terribly urge urgent urgently variously
たえず の訳語→ ceaselessly constant endless invariably permanently perpetual
ひっきりなしに の訳語→ constantly continuous incessant steadily steady unceasing