肺癌易形成空洞的是()
A.腺癌
B.鳞癌
C.未分化癌
D.肺泡细胞癌
E.转移性肺癌
参考答案:B
斜弯曲的主要特征是( )。
A.My≠0,Nx≠0,Nx≠0,中性轴与截面形心主轴不一致,且不通过截面形心B.My≠0,Nx≠0,Nx≠0,中性轴与截面形心主轴不一致,但通过截面形心C.My≠0,Nx≠0,Nx≠0,中性轴与截面形心主轴平行,但不通过截面形心D.My≠0,Nx≠0,Nx≠0,中性轴与截面形心主轴平行,但不通过截面形心
The light on a life jacket must be replaced().
A.when the power source is replaced
B.each year after installation
C.every six months
D.when it is no longer serviceable