管涵施工注意事项中,涵洞完成后,当涵洞砌体砂浆或混凝土强度达到设计强度的( )时,方可进行回填土。
A.45%
B.55%
C.65%
D.75%
参考答案:D
Please introduce your family. [ ]
A. I love my father and mother.
B. This is my father and mother.
根据我国专利法规定,发明专利的保护范围以______为准。
A.专利请求书
B.专利说明书
C.专利摘要
D.权利要求书