back up

1drive or move backwards倒车

He had to back his car up because the mountain path was too narrow.由于山路太窄,他不得不把车子倒了回来。

2support 支持

I hope you will back me up in this argument.我希望在这场争论中你能支持我。

Nobody backed her up when she protested against the decision.当她反对这项决定时,没人支持她。

3block hold up阻塞

The vehicles were backed up because of the accident.车辆因交通事故受阻了。