There was only one seat free on the train.

火车上只有一个空座。

《柯林斯英汉双解大词典》

There's only one seat so you'll have to sit on my lap.

只有一个座位，你只好坐在我腿上了。

《牛津词典》

It was a different seesaw with only one seat.

这个跷跷板还真与众不同，只有一个座位。

youdao

In a by-election where there is only one seat up for grabs, it effectively becomes an "alternative vote" contest.

BBC: Labour wins South Lanarkshire Council majority

Moreover, the Democrats are only one seat away from taking over the Senate.

ECONOMIST: Lexington

His Party of Democratic Patriots won only one seat on the constituent assembly, but he led efforts to unite several leftist parties in October.

WSJ: Tunisia Assassination Upends Government