油泵正常工作必备的条件是什么？

下列说法：①锐角的补角一定是钝角；②一个角的补角一定大于这个角；③如果两个角是同一个角的余角，那么它们相等；④锐角和钝角互补．其中，正确的说法有（　　）

A．1个

B．2个

C．3个

D．4个

阅读材料，回答下列问题：

材料：鸦片战争后，外国列强不断发动对中国的侵略战争，从鸦片战争到八国联军侵华战争，签订了一系列不平等条约，中国一步步变成了一个半殖民地半封建国家，中 * * 陷入苦难深重和极度屈辱的深渊。中国民族危机不断加剧，中 * * 与外国列强的矛盾日趋激烈，中国人民在国势日益沉沦中同仇敌忾，进行了顽强抗争，为捍卫国家主权和民族尊严，谱写了可歌可泣的反侵略斗争篇章。这是鸦片战争后至20世纪初年中国近代历史发展的一条鲜明主线。

（1）列举出中国近代史上，与列强签订的三个最严重的不平等条约，并说出其中一个条约的影响。

（2）俗话说“兵来将挡，水来土掩”，面对列强侵略，中国人民在国势日益沉沦中进行了顽强的抗争，请你列举出中国人民武装反抗外来侵略斗争的事例三例。武装反抗外来侵略的英雄人物一例。

A small town in Tasmania, an island off the south coast of mainland Australia, is making itself an environmental role model by becoming the country's first plastic bag-free town.

Since April 28, Coles Bay's population of 175 and its tourist shoppers have been using reusable paper or cloth bags to carry their shopping.

Ben Keamey, a local businessman who supports the bag ban, said it would cut  the amount of waste and prevent damage to native wildlife that try to eat the plastic.

"Most businesses here come from the tourism and that's all based on the environment, so people were pretty supportive," he said.

Every year Australians use more than six billion plastic bags. More than half of these come from the supermarket. Since it takes years for the bags to biodegrade（生物递减分解）, tens of millions end up polluting the environment. They kill about 100,000 sea-birds and animals, which mistake bags for food, every year.

Only in the past few months have major Australian supermarkets begun cutting on their use of plastic bags. Environmental groups are pushing for a plastic bag fee like that in Ireland. There, since plastic bags cost 10 pence (about 1 yuan) each, their use has been cut by 90 per cent.

Pollution caused by plastic bags is a big headache for countries all over the world. As early as 1999, Beijing said that only plastic bags of certain thickness could be used. This was to encourage them to be used again and again, since an average of six million plastic bags are used there every there every single day.

小题1:Which might be the best title for this passage?

A．Deadly Plastic Bags

B．The End of Plastic Bags

C．How to Reuse Plastic Bags

D．The Present Situation of Plastic Bags小题2:Plastic bags will not be used by the native people of Coles Bay because they ______.

A．cause the environmental pollution

B．are not easy to be reused

C．are not as good as cloth bags

D．are not strong enough小题3:Which of the following statements is NOT true?

A．Plastic bags kill many animals in Australia each year.

B．Most Australian supermarkets have begun cutting on their use of plastic bags.

C．People at Coles Bay think poor environment may affect their tourism.

D．You have to pay for the plastic bags if you go shopping in Ireland.小题4:The example of Coles Bay is to show that ______.

A．people take serious actions to deal with the plastic bag problem

B．people begin to realise the harm of using plastic bags

C．Australia is the first country in solving the plastic bag problem

D．Australians are aware of the importance of protecting the small town小题5:Which of the following measures on plastic bags is NOT mentioned in the passage?

A．To forbid to use them by law.

B．to charge fee for plastic bags.

C．To make them thick enough to be reuseable.

D．To make them environmentally friendly.

直肠癌生长环绕肠管一周约需（）.

A.>36个月

B.<6个月

C.6～9个月

D.24～36个月

E.12～24个月

在周围一无所有的的自由空间，从天线辐射的电场强度E₀与（）无关。