小明同学在校园里记录了所看到的生物和它们的生活环境,并把它们进行归类,他采用的科学方法是( )
A:调查
B:观察
C:比较
D:分析
瓦子在宋代城市盛行的主要原因( )
用括号内所给动词的适当形式填空Tom,____(not stay) out too late.____ _______ your uncle ______ (clean) his car every week?Tom with his brother____ (chat) with each other on the Internet now.I usually spend thirty minutes____ (read) English in the morning.Is it important for us____(drink) lots of water every day.There____(not be) any calories in water. So you can drink it without getting fat.People all like the game ____ (call)‘trick or treat’in the USA.Players need lots of energy ____ (run) every day.ooThe boss often makes his workers ____ (work) for 12 hours.Look! The boy____ (have) a comic book in his hand.
与东经120°经线构成经线圈的经线是( )
已知函数f(x)=x3﹣x+2 x .
(Ⅰ)求函数y=f(x)在点(1,f(1))处的切线方程;
(Ⅱ)令g(x)= ax2+axf(x)−2x +lnx,若函数y=g(x)在(e,+∞)内有极值,求实数a的取值范围;
(Ⅲ)在(Ⅱ)的条件下,对任意t∈(1,+∞),s∈(0,1),求证: g(t)−g(s)>e+2−1e .
阅读下列材料,回答问题。
材料一:十二届全国人大五次会议15日表决通过了《中华人民共和国民法总则》。
材料二:从1954年至2002年近半个世纪,曾先后四次组织民法的起草,但都半路夭折或未实现预期的目标。2014年十八届四中全会研究通过《中共中央关于全面推进依法治国若干重大问题的决定》,明确提出“编纂民法典”的重要立法任务,由此为基点,民法典编纂进入快车道。下图为《民法总则》的制定过程:
材料三:马克思说,法典是人民自由的圣经。