Most competition cars will only roll over if they hit an obstacle.

多数赛车在撞到障碍物时才会翻车。

He left her to navigate her own way round the trolleys and other obstacles.

他留下她独自在手推车和其他障碍物中间穿插行走。

Overcrowding remains a large obstacle to improving conditions.

过度拥挤仍然是改善条件的一大障碍。

To succeed, you must learn to overcome obstacles.

要成功，你就必须学会克服障碍。