The ban was imposed because once the ash cloud, as predicted by VAAC London, had spread out far enough it was hard to get any routes through it.
颁布禁飞令是因为一旦如伦敦VAAC所预测那样，火山灰扩散甚远，航班就难以飞过火山灰所覆盖的航线。
youdao
应用推荐
模块上移
模块下移
不移动