尼古丁是一种剧毒物质,烟草中含有尼古丁,所以,烟草是一种剧毒物质。此推理所犯的错误叫做()
A.四概念
B.中项不周延
C.两否定前提
D.大项不当周延
参考答案:A
My uncle remembered ______.[ ]
A. when we moved to the town
B. when did we move to the town
C. when we move to the town
D. when do we move to the town
桥位制梁常见的支架型式有()
A.满堂红脚手架杆
B.门式脚手架
C.钢管立柱和贝雷梁组合支架
D.附着式脚手架