阅读下面短文，按照句子结构的语法性和上下文连贯的要求，在空格处填入一个适当的词或使用括号中词语的正确形式填空，并将答案填写在答题卡相应位置。
Unprecedented Aviation Mystery
A Boeing 777 took off from Malaysia’s largest city of Kuala Lumpur at 0:41 am on March 8.
小题1:_____destination was Beijing. But the flight never arrived, 小题2:______ （leave） friends and relatives of the passengers onboard weeping and worrying.
There were 239 people小题3:____   board the Malaysia Airlines flight，including China， Vietnam，the US，Singapore， and the Philippines 小题4:_______ still ______ （search）for the missing plane.
Its 小题5:__________ （disappear）is an "unprecedented（史无前例的）aviation mystery”， Azharuddin Abdul Rahmanm，head of Malaysia’s Civil Aviation Authority，said on March 10.
There was no sign of 小题6:____   crash.
About two hours of after taking off，air traffic control suddenly lost contact with the plane. The weather was clear，the pilots didn't make any distress calls，小题7:       no debris 碎片） was found in the area 小题8:______ the flight last made contact.
Besides，airplane crashes小题9:________ （typical）occur during takeoff or landing. Only 9 percent of fatal accidents happen 小题10: ______ a plane is at cruising（平稳行进的）altitude，according to a report by Boeing in August.