李某转让拥有产权的房屋一套，取得转让收入40000元。此间房屋的原价为30000元，

引起皮肤组织坏死形成溃疡的主要因素是（）

A.保护性抗原（PA.

B.致死毒素（LT）

C.水肿毒素（ET）

D.荚膜

E.内毒素

随着宫缩增加，羊膜腔内压力增加到一定程度即可发生自然破裂，临床上一般宫颈扩张为____________cm时破膜最佳。

The home of the future won’t be completely different and we will be living in houses and flats just as we do today. But people will want to shape their homes to match their dreams. No two homes will be the same. People will be able to buy “house kits” containing a basic house structure, with movable walls, doors and windows. They will put together the different parts to create the home they want.

Many jobs that we do today will disappear, others will still exist but will change and new jobs will be created. Skilled workers such as builders, gardeners and electricians won’t disappear because machines can’t replace them. Teachers will still exist because students need human contact. But they will be using modern technology in class more and students will be working more from home. The medical technology revolution and space travel will create new jobs which we can only imagine today.

Space holidays will develop in the future, but these holidays won’t be for everyone because they won’t be cheap. Short space trips will develop first, then space hotels will orbit the earth where it will be possible to have a longer vacation. By the end of the next century, there will be holiday centres on the moon with leisure facilities for families.

Paper won’t exist in the future. Instead, there will be e-paper which people will be able to use over and over again. This will develop in order to save natural resources. E-newspapers and e-magazines will replace traditional newspapers and magazines and we will download information and news articles from the Internet every day onto our reuseable paper.

The laws of physics tell us that the earth is going to disappear some time in the future. This isn’t going to happen tomorrow but scientists predict that it will happen in five billion years when our sun explodes（爆炸）.We will have to explore the universe and find another home. At some point in the distant future, either we stay on the earth and die with it, or we leave and move to another planet. There won’t be any other choice.

60．Homes of the future will ________.

A．be completely different from those of today.

B．be very similar to our homes

C．all be different form one another                 

D．be movable as you want

61．Space trips and staying in space hotels will _________.

A．become a very common way to spend a holiday

B．be the cheapest holiday option for families

C．attract a lot of people

D．still only be for very rich people

62．E-paper will replace traditional paper because _________.

A．we will use it again  B．it won’t waste natural resource

C．it will be cheaper to produce   D．it will be convenient to carry

63．We will have move to another planet ________.

A．if we want to save the human race  B．when the sun explodes

C．when the earth disappears       D．when the earth is too crowded to fill people on

气雾剂中的氟利昂(如F₁₂)主要用作()。

A．助悬剂

B．防腐剂

C．潜溶剂

D．消泡剂

E．抛射剂

摩擦系数小，有较高的精度及寿命的轴承是（）。

A.滑动轴承

B.非金属轴承衬

C.滚动轴承

D.金属轴承衬