问题 选择题
下列有关命题的说法正确的是(  )
A.若p∨q为真命题,则p,q均为真命题
B.命题“∃x0∈R,
x20
-x0+1≤0
”的否定是“∀x∈R,x2-x+1≥0”
C.“-3<k<3”是“方程
x2
3-k
+
y2
k+3
=1
表示椭圆”的充要条件
D.“直线与双曲线有唯一交点”是“直线与双曲线相切”的必要不充分条件
答案

A.若p∨q为真命题,则p,q至少有一为真命题,所以A错误.

B.命题“∃x0∈R,

x20
-x0+1≤0”的否定是“∀x∈R,x2-x+1>0”,所以B错误.

C.当k=0时,方程为

x2
3
+
y2
3
=1为圆,所以C错误.

D.当直线与渐近线平行时,直线也与双曲线有唯一交点,但此时直线与双曲线不是相切,是相交.

所以D正确.

故选D.

阅读理解

阅读理解。

     Being considered a leader in our society is indeed of high praise. Leadership means power, commands

respect and, most important, encourages achievement. Unlike vitamin C, leadership skills can't be easily

swallowed down. They must be carefully cultivated.

     Different from popular belief, most good leaders are made, not born. They learn their skills in their

everyday lives. But which do they develop? How do they (and how can you) get others to follow?

     Always give credit. Many leaders note that the most efficient way to get a good performance from

others is to treat them like heroes. Giving public credit to someone who has earned it is the best leadership

technique in the world. It is also an act of generosity (慷慨) that's never forgotten.

     Giving credit is more effective than even the most constructive criticism (批评), which often hurts

rather than helps. Kenneth Blanchard, the author of The One-Minute Manager, agrees.

     "Catch people doing something right!" he says. Then tell everyone about it.

     Take informed risks."The best leaders know that taking a risk is not a thoughtless exercise," says

management adviser Marilyn Machlowitz."Sky divers don't go up in an airplane without checking the

parachutes (降落伞) beforehand."

     Because the idea of risk also carries with it the possibility of failure, many of us usually wait for others

to take charge. But if you want to be a leader, you must learn to fail - and not die a thousand deaths. Pick

yourself up and start all over again.

     Encourage enthusiasm. (热情) "When people understand the importance of work, they lend their mental

strengths," says Lee Ducat. But when they get excited about the work, all their energy gets poured into the

job. That's a great force! Is this the best way to create excitement? Be enthusiastic yourself-You will be

followed by everyone.

1. The underlined word "cultivated" ( paragraph 1 ) roughly means ______.

A. encouraged

B. compared

C. examined

D. developed

2. The part Always give credit tells us that a leader should ______.

A. give helpful criticism

B. regard others as real heroes

C. praise people for their good performances

D. praise everyone

3. To be a good leader, you should ______.

A. not be afraid of any risks

B. think twice before taking risks

C. try to avoid any possible failures

D. know what a thoughtless exercise is

4. Which of the following can be the best title for the passage?

A. Leadership Is of Skills and Techniques

B. Leadership Is Very Important

C. Not Many Can Be Leaders

D. How to Be a Leader

多项选择题