13. It's lucky that everyone survived from the airplane crash.
幸运的是所有人在这次空难中幸免于难。
还能这样说：
Luckily, nobody was killed in the airplane crash.
Luckily, all the passengers were alive in the airplane crash.
14. They tried to find the cause of the aviation accident.
他们试图找到飞机失事的原因。
还能这样说：
They tried to investigate what caused the aviation accident.
They made an attempt to determine the reason why the airplane crash happened.
15. I was sorrowful for the victims of the air crash.
我为空难中的遇难者感到悲痛。
还能这样说：
My heart bled for the deceased of the air crash.
I mourned for the dead in the airplane accident.
应用解析：
out of thin air 无中生有；
put on airs 装腔作势；
live on air 喝西北风过日子，饿肚子过活
16. The wreckage was distributed all over the area after the plane crashed on the land.
飞机坠毁后，残骸散落一地。
还能这样说：
The wreck of the crashed plane was scattered on the land.
There was a lot of debris scattered over the land after the plane crashed.
17. The plane cracked up by the lightning.
飞机遭雷击而坠毁。
还能这样说：
The plane crashed and struck by the lightning.
The airplane was struck by thunderbolt and then crashed.
应用解析：
have a crack at 试一试，（在某件事上）试一试自己的能力；
in a crack 片刻间，转眼间；
the crack of doom 世界末日，最后审判日的雷声