下列计算正确的是[ ] A.2a+2b=4ab B.3x2﹣x2=2 C.5mn 发布时间:2017-05-22 10:56 │ 来源:www.tikuol.com 题型:选择题 问题: 下列计算正确的是[ ]A.2a+2b=4abB.3x2﹣x2=2C.5mn﹣5nm=0D.a﹣a=a2
题型:选择题 In more recent years,()has been used by civilians in many new ways to determine positions,such as in automobile and boat navigation,hiking,emergency rescue,and precision agriculture and mining.A.GPSB.GMDSSC.AISD.Navtex 查看答案