不定代词中表示“两者”和“三者”的考点

一、"两者"与"三者"有些不定代词只用于表示两个人或两个事物,它们是both,either和neither;而有些不定代词则只用于指三个或三个以上的人或事物,它们是all,any,none和every。在使用时千万不要弄混了。如:     

学会使用表示“推测”的情态动词

表示推测的情态动词常见的有can,could,may,might,must,should。现分别讲解如下：     

一般现在时态“新同发布会”

主持人：同学们,一般现在时态“新闻发布会”现在开始啦!首先请发言人向大家介绍一下一般现在时。发言人：感谢主持人。一般现在时态用来表示时间发生的动作或行为,或是习惯的动作或行为,或是普遍真理。例如：     

伏安特性曲线的典型应用

在同一坐标系中作出电阻、二极管等元件的伏安特性曲线,根据该曲线巧妙确定元件在电路中的工作点,进而由工作点的坐标即可知元件在实际工作状态下的电流、电压．所以,指导学生运用该图象分析讨论某些物理问题不仅简便易行,而且可以深刻理解物理概念和物理规律．     

探究一道高考压轴题的解法

试题：已知曲线Cn：x^2-2nx＋y^2=0（n=1,2,…）．从点P（-1,0）向曲线Cn引斜率为kn（kn〉0）的切线In,切点为Pn（xn,yn）．     

重视数学符号感的培养

罗素说过:"什么是数学?数学就是符号加逻辑。"数学对象的空间位置结构、数量关系等都是以符号的形式来表示的,数学符号是数学的语言,是人们进行表示、计算、推理、交流和解决问题的工具,它具有准确、清晰、简约思维、提高效     

非对称效应视角下的中国通货膨胀不确定性实证研究

基于中国1983.01-2009.02月度CPI数据,应用多种非对称GARCH模型与信息冲击曲线研究通货膨胀冲击的非对称特征,并检验1996年货币供应量中介目标的引入是否明显降低了通货膨胀不确定性的长期成分。结果发现,通货膨胀冲击存在非对称特征,由通货膨胀冲击引发的通货膨胀不确定性高于同等程度通货紧缩冲击引发的通货膨胀不确定性;而1996年中央银行开始实行的货币供应量作为货币政策中介目标的适宜性虽然受到了不断的质疑,但其客观上确实一定程度降低了通货膨胀不确定性的长期成分。     

Determination of 5-Fluorouracil in Human Plasma by High- Performance Liquid Chromatography （HPLC

5-Fluorouracil (5-FU) has a broad spectrum of anti-tumor activity, widely applied to the treatment of cancers. However, it is necessary to determine the plasma concentration of 5-FU in clinical practice due to its narrow therapeutic index. Therefore, a simple, economic and sensitive high-performance liquid chromatography (HPLC) method was developed and validated for the determination of 5-FU in human plasma. Ethyl acetate was chosen as extraction reagent. Chromatographic separation was performed on a Diamonsil C18 column (250 mm × 4.6 mm i.d., 5 μm) with the mobile phase consisting of methanol and 20 mmol/L ammonium formate using a linear gradient elution at a flow rate of 0.8 mL/min. 5-FU and 5-bromouracil (5-BU) were detected by UV detector at 265 nm. The calibration curve was linear over the concentration range of 5—500 ng/mL and the correlation coefficient was not less than 0.992 6 for all calibration curves. The intra- and inter-day precisions were less than 10.5% and 4.3%, respectively, and the accuracy was within ±3.7%. The recovery at all concentration levels was 80.1±8.6%. 5-FU was stable under possible conditions of storing and handling. This method is proved applicable to therapeutic drug monitoring and pharmacokinetic studies of 5-FU in human.     

函数与不等式证明综合题

途径一依据函数特征,利用不等式的性质适度放缩,分析法与综合法有机结合。【例1】已知a>0,函数f(x)=ax-bx~2.(1)当b>0时,若对任意x∈R都有f(x)≤1,证明a≤2b~(1/2);(2)当b>1时,证明对任意x∈