One-horse race:

一匹馬的比賽 ×

勝負(fù)分明的比賽 √

例句：

He described the election as a one-horse race.

他稱這次選舉是一場勝負(fù)分明的比賽。

One-horse town:

一匹馬的城鎮(zhèn) ×

鄉(xiāng)村小鎮(zhèn) √

例句：

This was a one-horse town, a beautiful quiet place.

這里以前是個(gè)鄉(xiāng)村小鎮(zhèn)，寧靜而又景色秀麗。

Don't ride the high horse:

不要騎高馬 ×

不要擺架子 √

例句：

You are not my boss, don't ride the high horse.