如图所示结构1、2杆轴力为( )。A.N1压力,N2拉力 B.N1×N2<0 C. 发布时间:2017-06-04 07:42 │ 来源:www.tikuol.com 题型:单项选择题 问题: 如图所示结构1、2杆轴力为( )。A.N1压力,N2拉力B.N1×N2<0C.N1拉力,N2拉力D.N1=N2=0
题型:单项选择题 —Where does your father work, Lucy?—In England. But he ________ in France for 8 years.[ ]A. has worked B. has been workedC. have been working D. worked 查看答案
题型:单项选择题 下列说法何者正确( )A.肺炎支原体可在无细胞的培养基中生长B.肺炎支原体亦称为“典型性肺炎”C.鹦鹉热衣原体主要引起鹦鹉疾病D.肺炎衣原体可在无细胞的培养基中生长肺炎衣原体主要引起沙眼E.肺炎衣原体主要引起沙眼 查看答案