20.advise you alter course to port side. advise you alter course to starboard side.

建议你船向左转向。建议你船向右转向。

50.it is dangerous to alter course to port side.

向左转向是危险的。

It is dangerous to alter course to starboard.

向右转向很危险。

51.it is dangerous to alter course to starboard side.

向右转向是危险的。

When the plane abruptly altered course to make the unplanned landing in Minsk, fellow passengers recalled him saying he would be executed in Belarus.

据其他乘客加快，当飞机突然改变航向并计划外地在明斯克降落时，普罗塔塞维奇说自已会在白俄罗斯被处决。