For that reason Coco was, to me, 'an older sister I can play with' and I thought of her only as one member of the family not as someone I should question my father concerning her identity.
しかし僕だけではなく、もうひとり—いや、もう一匹の珍客がいたらしい。
However, it was not just me – there was one more person, no, one more creature visiting.
老人はたったひとりで座っていた。
The old man sat all alone.
両親は長い間反対していたが、ついに彼女がヨーロッパにひとりで行くことを許した。
Although her parents had said no for a long time, they finally let her go to Europe alone.
由美は、私の友達のひとりです。
Yumi is one of my friends.
夜明けにたったひとり列車を降りて。
Step off the train all alone at dawn.
夜こんなに遅くひとりで出かけるなんて言い張ってはいけません。
You must not insist on going out alone so late at night.