发明专利权的期限为（）A．10年 B．15年 C．20年 D．30年

低级别的试剂可以“升级”使用，同样可以将高级别的化学试剂少量地用于较低档次的实验。( )

有关合同承诺的叙述中，不正确的是( )。

A．非受要约人或未获得授权的代理人不得作出承诺
B．超过要约规定的期限或合理期限的承诺无效，只能视为一个新要约
C．一项有效的承诺，受要约人不能对要约内容作出实质性变更，否则为新要约，并导致原要约失去效力
D．如果受要约人内心愿意接受要约，却保持沉默，未对要约人公开表示却私下为该合同作出准备工作的，可以构成承诺

商业计划书的使用方式上，下列描述不正确的是（）。

A、先撰写完整的商业计划书再开始创业

B、行动本身能验证计划

C、需要随时调整

D、企业做到一定规模才有撰写商业计划书的必要

某多层钢结构厂房，为一购物中心工程，总建筑面积约21200㎡，主体为三层钢框架结构局部四层，结构安全等级为二级。檐口总高度为19m，框架钢柱为焊接箱型柱，钢梁为焊接H型钢梁，楼面为压型钢板与混凝土叠合楼板，外墙面为压型彩板。主钢构件材质为Q345，檀条采用Q235C型薄壁型钢。主要构件焊接质量等级为二级，本工程施工范围包括钢结构系统的制作与现场安装施工。请根据背景资料完成以下选项

关于高强螺栓连接施工，下述说法不妥当的是（）。

A、高强螺栓连接应对构件摩擦面进行喷砂、砂轮打磨或酸洗等加工处理

B、安装前应逐组复验摩擦系数，合格后方可安装

C、高强螺栓的紧固，应分初拧和终拧二次拧紧

D、高强螺栓允许超拧，不允许欠拧、漏拧

When I was growing up, I was embarrassed to be seen with my father. He (1) severely crippled and very short, and when we would walk together, his hand on my arm (2) balance, people would stare. I would inwardly be afraid (3) squirm at the unwanted attention. If he ever noticed or was bothered, he never let (4) .
It was difficult to coordinate (5) steps - his halting, mine impatient - and because of that, we didn’t say much as we went along. But as we started out, he always said, "You (6) the pace. I will try to adjust to you. "
Our usual walk was to or (7) the subway, which was how he got to (8) . He went to work sick, and (9) nasty weather. He almost never missed a day, and would (10) it to the office even if (11) could not: a matter of pride!
He never talked about himself as an object of pity, (12) did he show any envy of the more fortunate or able. What he looked for in others was a "good heart", and if he found one, the owner was good enough for him.
Now that I am older, I believe that is a proper standard (13) which to judge people, even though I still don’t know precisely (14) a "good heart" is. But I know the times I don’t have one myself.
He has (15) gone many years now, but I think (16) him often. I wonder if he sensed my reluctance to be seen with him during our (17) . If he did, I am (18) I never told him how sorry I was, how unworthy I was, how I regretted it. I think of him when I complain about trifles, when I am (19) of another’s good fortune, when I don’t have a "good heart".
At such times I put my hand on his arm to regain my (20) , and say, "You set the pace, I will try to adjust to you.\