A ferry crosses the river every hour.

渡船每小时过河一次。

They could not cross the river owing to the flood.

由于洪水，他过河。

Before the enemy's attack he crossed the river and alarmed the unarmed villagers.

在敌人进攻前, 他过河去向手无寸铁的村民警。

Therefore, the water-surface crossing with mobile flexible pipelines is often adopted and it is a first choice to cross an innavigable river.

软管水面穿越河流具有铺设迅速,检修方便,容和使用等优点,尤其是对于通航河流,是软质机动管线临时穿越河流的首选方式。