1.Aircraft manufacturer Boeing has grounded the entire global fleet of its 737 Max aircraft.
ground 使停飞
The civil aviation minister ordered all the planes to be grounded.
该民航部长命令所有飞机不得起飞。
2.and will study the data in them to ascertain the reason for the aircraft falling from the sky.
ascertain 查明
It can be difficult to ascertain the facts.
可能难以查明事实真相。











