(文)若命题p:对∀x∈R,x2+4cx+c>0为真命题,则实数c的取值范围是_

题型:填空题

问题:

(文)若命题p:对∀x∈R,x2+4cx+c>0为真命题,则实数c的取值范围是______.

考点:真命题、假命题
题型:填空题

When I was 16 years old, I made my first visit to the United States. It wasn’t the first time I had been abroad. Like most English children, I learnt French at school and I had often been to France, so I was used to speaking a foreign language to people who didn’t understand English. But when I went to America I was really looking forward to having a nice easy holiday without any language problems.

How wrong I was! The misunderstanding began at the airport. I was looking for a public telephone to give my American friend Danny a ring and tell her that I had arrived. A friendly old man saw me looking like being lost and asked if he could help me.

“Yes,”I said.“I want to give my friend a ring.”

“Well, that’s nice,”he exclaimed (惊呼).“Are you getting married? But aren’t you a bit young?”

“Who is talking about marriage?” I replied. “I just want to give my friend a ring to tell her I’ve arrived. Can you tell me where there’s a phone box?”

“Oh!”he said.“There’s a phone downstairs.”

When at last we did meet up, Danny explained the misunderstanding to me.“Don’t worry,” she said to me.“I had many difficulties at first. There are lots of words which the Americans use differently in meaning from us British. You’ll soon get used to all the funny things they say. But most of the time British and American people can understand each other!”

小题1:When the writer arrived at the airport, he wanted to _____.

A.buy a ring for his friend

B.ask the way to his friend’s

C.telephone his friend

D.call a taxi小题2:The old man thought _____.

A.the writer wanted to find a phone box

B.the writer was old enough to get married

C.the writer didn’t know the way

D.the writer wanted to find his girlfriend小题3:.At last, the old man _____.

A.understood what the writer wanted to do

B.couldn’t understand the writer

C.bought a ring for the writer

D.took the writer to the phone box by himself小题4:Which sentence is wrong according to the passage?

A.The writer’s friend, Danny had a lot of difficulties in the U.S.A. at first.

B.There are some differences between American and British English.

C.British people can’t understand the Americans most of the time.

D.British and American people can understand each other most of the time.

题型:填空题

爱因斯坦的相对论指出:主体选择不同的参照系对同一物理事件或物理过程进行时、空度量,所得的结果可能不一样。在认识论上来说是

A.真象和假象的区别所造成的

B.现象和本质的矛盾所造成的

C.主体和客体的关系的变化所造成的

D.由于主观认识的错觉所造成的

题型:填空题

实验室制取0.4g氢气需要多少克锌与足量的稀硫酸反应?若改用含杂质10%的锌粒与稀硫酸反应(杂质不与酸反应),需要这种锌粒多少克?

题型:填空题

腹胀满,无压痛,叩之作空声,可见于

A.水臌

B.气胀

C.痰饮

D.积聚

E.内痈

题型:填空题

抑制延脑咳嗽中枢而产生镇咳作用的药物是()

A.二丙酸倍氯米松

B.可待因

C.沙丁胺醇

D.氨茶碱

E.色甘酸钠

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