The sea was now quite smooth, and as, from some cause which we could not determine, the brig did not lie so much along as she had done before, the deck was comparatively dry, and we could move about with freedom. (The Narrative of Arthur Gordon Pym of Nantucket by Edgar Allan Poe）注：時化にあった後の船の様子です。brig = 船（２本マストの帆船）
動画の後半部分でリスニング用音声が流れます。
英文を前から読んでいくために、語句のかたまりを作ります。こんな具合に課題文をスラッシュ（斜め線）で区切ります（スラッシュリーディング）。語句のかたまりを意識すると、リスニングで英語の意味をつかむのが楽になります。
The sea was now quite smooth,／（接続詞の前）and as, from some cause which we could not determine,／（主語が文頭にないときの主語の前）the brig did not lie so much along as she had done before,／（主語が文頭にないときの主語の前）the deck was comparatively dry,／（接続詞の前）and we could move about with freedom.
語句のかたまりを前から訳していきます。
The sea was now quite smooth,
今や海はすっかり穏やかになった
and as, from some cause which we could not determine,
そして、はっきりしない何らかの理由によって、〜ので
the brig did not lie so much along as she had done before,
船は以前より横に傾かなくなっていた
the deck was comparatively dry,
甲板はかなり乾いていた
and we could move about with freedom.
そして、私たちは自由に動き回ることができた
今や海はすっかり穏やかになった。はっきりしない何らかの理由によって、船は以前より横に傾かなくなっていたので、甲板はかなり乾いており、私たちは自由に動き回ることができた。
as, from some cause which we could not determine, the brig did not lie so much along as she had done before, the deck was comparatively dry, and we could move about with freedom
この部分の構造が少し複雑になっていますが、from〜 の挿入語句をカッコでくくると、意味がわかりやすくなります。
as（,from some cause which we could not determine,）the brig did not lie so much along as she had done before, the deck was comparatively dry, and we could move about with freedom→ カッコ部分を省くと→ as the brig did not lie so much along as she had done before, the deck was comparatively dry, and we could move about with freedom
as the brig did not lie so much along as she had done before,（ここまでが理由［〜なので］で、この後に「どういう状態なのか」が示されます）the deck was comparatively dry, and we could move about with freedom
