题型:选择题 Great changes ____________ in my hometown in the past few years.A.took placeB.have taken placeC.have been happenedD.broke out 查看答案
题型:单项选择题 10mm(0.4英寸)焊角角焊缝的理论焊喉尺寸为()A.5mm(0.2inches)B.7mm(0.3inches)C.10mm(0.4inches)D.13mm(0.5inches) 查看答案