まだ、まとめの途中。
My iPhone has broken and I want to buy one.
one の前に形容詞が付くと a が付く。
My iPhone has broken and I want to buy a new one.
It can store twice as many bicycles as a standard one.
The population of the US is larger than that of Japan.
Most people in the community are more conservative than those in other areas.
one に the が付く時。
The girl I was talking with was younger than the one you were dancing with.
それが人でなければ、the one は that にできる？
The computer is faster than the one we have been using.
The computer is faster than that we have been using.（これは関係代名詞的にダメ？？？）
（？that は関係代名詞の先行詞になるうるのか？）
The temperature in this room is lower than that in the other room.
The temperature in this room is lower than the one in the other room.（これOK？？？）
まだよく分かりません。