An average of 130,000 Chinese       aboard for studies every year over the past few years, improving

exchanges in the educational fields. [      ]

A. was going      

B. have been going    

C. has been going    

D. are going

为防止伪造身份证件，有必要采用（）形式。①数据条码形②水印③单纯的使用加塑封

A.①

B.①或②

C.③