单项选择题
A.100 tons B.Not clear C.More than 100 tons D.I don’t know
Where is the most air freight shipped in the passenger ...
单项选择题Where is the most air freight shipped in the passenger aircraft?（）
A.Separately B.In same level C.In the lower part D.Not mention here
How much is the percent of air transportation in all mo...
单项选择题How much is the percent of air transportation in all modes?（）
A.Less than 1% B.Lowest C.Lower D.Low
What kind of products do the air carriers deliver? （）A....
单项选择题What kind of products do the air carriers deliver? （）
A.The high value B.Low density or weight C.A and B D.Shortest time to transport
