单项选择题
How many categories are there in water transport?（）
A.2 B.3 C.4 D.Not available in the paragraph
单项选择题 How many tons does the cargo 737 carry?（）
单项选择题 Where is the most air freight shipped in the passenger aircraft?（）
单项选择题 How much is the percent of air transportation in all modes?（）
