单选题甲花费5万元购买了股票，随后他将这些股票转卖给乙，获利10%，不久乙又将这些股票返卖给甲，但乙损失了10%，最后甲按乙卖给他的价格的9折把这些股票卖掉了，不计交易费，甲在上述交易中______．

单选题设f(x-3)=e2x，则f"(x)=______

单选题[2015年12月]已知f(x)=x 2 +ax+b。则0≤f(1)≤1。 (1)f(x)在区间[0，1]中有两个零点； (2)f(x)在区间[1，2]中有两个零点。

单选题直线x=2，y=2与圆(x一1) 2 +(y一1) 2 =1分别相切于A、B两点，与劣弧AB相切于该劣弧中点的直线方程为( )．

单选题关于X的方程X2+2(m-2)X+m2=0有两个不相等的实数根，则k的取值范围是( )。 A．m＞1 B．m＜1 C．m＞-1 D．m＜-1

单选题Supporters of abortion rights held a lunch recently in honor of a momentous victory for their cause: 40 years ago, New York became the first state to fully legalize abortion. That 1970 law began to reduce the death and injury toll from back-alley abortions and set the stage for the Supreme Court's Roe v. Wade decision in 1973, which made abortion legal nationwide and recognized a constitutional right to privacy. But abortion-rights groups are newly anxious about new assaults on women's reproductive rights, including a fight over abortion that snarled the last days of the health care reform debate. Anti-abortion groups are newly emboldened. Kelli Conlin, head of Naral Pro-Choice New York, told guests at the lunch that "anti-choice forces are mobilizing in every single state to limit a woman's access to abortion in more insidious ways than we can imagine. " As Ms. Conlin was speaking, members of the Oklahoma House were getting ready to override vetoes of two punishing abortion measures. The state's Democratic governor, Brad Henry, rightly viewed these intrusions into women's lives and decision-making as unconstitutional. One of the measures, which seems destined to spawn copycat bills in other states, requires women to undergo an ultrasound before getting an abortion and further mandates that a doctor or technician set up the monitor so the woman can see it and hear a detailed description of the fetus. The other law grants protection from lawsuits to doctors who deliberately withhold fetal testing results that might affect a woman's decision about whether to carry her pregnancy to term. Several states have either passed or are considering bills that would ban abortion coverage in insurance plans sold through the state exchanges established by the federal health care law. A new Utah law criminalizes certain behavior by women that results in miscarriage. Embarking on a road that could lead to the Supreme Court, Nebraska last month banned most abortions at the 20th week of pregnancy based on a questionable theory of fetal pain. About two dozen states are looking at bills to increase counseling requirements or waiting periods prior to abortions. About 20 states are considering new ultrasound requirements. "One in three women in this country will have an abortion in her lifetime, and yet we're having exactly the same discussions and debates we were having forty years ago," Ms. Conlin said. Anti-abortion forces aim ultimately to make abortion illegal. So far, by reducing the number of abortion providers, making insurance coverage more expensive and harder to get, and throwing up other obstacles, they have primarily succeeded in making it harder for women of modest and meager means to obtain a safe and legal medical procedure. The painful decision to end a pregnancy should be made in private between a woman and her doctor—not in politically driven debate among members of Congress and state legislatures.

单选题下列四项中正确的是 ____ 。

单选题设α 1 ，α 2 ，α 3 是齐次方程组Ax=0的基础解系，那么Ax=0的基础解系还可以是______

单选题设向量组α1，α2，α3线性无关，向量组α2，α3，α4线性相关，则

单选题 要除去FeCl2溶液中含有的少量Fe3+和Cu2+，应选择的试剂是（??）

单选题已知x∈C，且，则的值为()。

单选题若，则=()

单选题3个质数的倒数之和是，则这3个质数之和为()．(A)334(B)335(C)336(D)337(E)以上答案均不正确

单选题由与过原点的这条曲线的切线及x轴所围图形的面积为______。A．B．C．1D．