But only chieftains could ride the massive olo boards, twice as long as today's longboards.

但只有酋长可以骑巨大的单人滑板，长度是今天长板的两倍。

It's " er" , so even though it's " olo" here, it becomes " er" .

是“er”，所以即使在这里是“olo”，也变成了“er”。