On March 8, the weather was fine. A plane--MH370 took off from Malaysia’s (马来西亚) capital Kuala Lumpier in the early hours of March 8. It was leaving for Beijing. But about two hours into the flight（飞行）, the plane disappeared(消失). There were 239 people on the Malaysia Airlines(马来西亚航空公司) flight(航班), including154 Chinese.
About 12 countries, including China and the US, have joined the search（搜寻） for the missing _①__ and__②____. The plane was flying at the height of more than 10,000 meters when it was suddenly lost. The pilots didn’t make any distress calls(求救信号). People said such clear weather couldn’t cause（引起） the accident. They also talked about that it might be a hijacking(劫机).
On March 25, Malaysia Airlines deeply said that the plane went down and ended in the Southern Indian Ocean and said no one survived(生还). ③They said they would continue(继续) to work in search of enough evidence(证据).
The plane’s disappearance was a “mystery”(神秘). This is a developing story. ④It could take months or even years to find out what happened to the flight.
在文中①、②处填写一个单词，使得句意完整、上下文通顺。____  _______
文中划线部分③的(they)指代的是___________
从文中找出两个修饰和描述天气的形容词。_____  ______
写出文中④句的同义句，每空限填一词。
People could ___________ months or even years ___________ out what happened to the flight .
从文中找出能说明本文中心大意的单词或者短语：___________