We went some distance up, to see the beautiful iron bridge which spans it, as also to have a look at the Oreston quarries, from which the material for forming the breakwater was principally procured.（A Yacht Voyage Round England by W.H.G. Kingston）
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。
IWe went some distance up,／（不定詞の前）to see the beautiful iron bridge／（関係代名詞の前）which spans it,／（コンマの後）as also to have a look at the Oreston quarries,／（前置詞の前）from which the material for forming the breakwater was principally procured.
語句のかたまりを前から訳していきます。
We went some distance up,
私たちは、いくらか川をさかのぼった
to see the beautiful iron bridge
そして、美しい鉄橋を見た
which spans it,
川にかかる
as also to have a look at the Oreston quarries,
また、オレストン採石場も見物した
from which the material for forming the breakwater was principally procured.
防波堤を作る材料の主な供給元だった
We went some distance up, to see the beautiful iron bridge which spans it, as also to have a look at the Oreston quarries, from which the material for forming the breakwater was principally procured.
We went some distance up→ go up =（川の上流へ）さかのぼる
from which the material for forming the breakwater was principally procured→ from which を本来の位置に戻す→ the material for forming the breakwater was principally procured from which→ which に先行詞を代入する→ the material for forming the breakwater was principally procured from the Oreston quarries→「防波堤を作る材料は主にオレストン採石場で手に入れられた」
私たちは、いくらか川をさかのぼり、川にかかる美しい鉄橋を見た。また、防波堤を作る材料の主な供給元だったオレストン採石場も見物した。
We went some distance up, to see the beautiful iron bridge which spans it, as also to have a look at the Oreston quarries, from which the material for forming the breakwater was principally procured.
今回の課題文には不定詞（結果）が２つ使われています。２つ目の不定詞を独立させて意味をとろうとすると訳せなくなるので、注意が必要です。不定詞（結果）は「（その結果）〜する」という意味です。
to see the beautiful iron bridge〜
We went some distance up＜
（as also）to have a look at the Oreston quarries
動画の後半部分でリスニング用音声が流れます。
