问题 多选题

水是一种宝贵的自然资源,下列关于水的说法中,不正确的是(  )

A.液态水结成冰,水分子变大,因而体积膨胀

B.通常情况下,水可以灭火,但不是任何场合都可以用水来灭火

C.水蒸发过程和水电解过程的不同在于分子的种类是否发生了改变

D.水中含两个氢原子和一个氧原子

答案

A、水分子间有间隔,液态水结成冰,水分子的间隔变大,所以,体积膨胀.水分子的大小没有变化.故A不正确;

B、通常情况下,水可以灭火,但不是任何场合都可以用水来灭火.例如,电线短路失火,不可用水灭火.故B正确.

C、水蒸发是物理变化,水分子本身不变;水电解是化学变化,水分子分成氢氧原子,氢氧原子重新组合成氢分子和氧分子,分子种类发生了变化.故C正确.

D、水是由水分子构成,一个水分子中含有两个氢原子和一个氧原子.故D不正确.

故选:AD.

单项选择题

People have good reason to care about the welfare of animals. Ever since the Enlightenment, their treatment has been seen as a measure of mankind’s humanity. It is no coincidence that William Wilberforce and Sir Thomas Foxwell Buxton, two leaders of the movement to abolish the slave trade, helped found the Royal Society for the Prevention of Cruelty to Animals in the 1820s. An increasing number of people go further: mankind has a duty not to cause pain to animals that have the capacity to suffer. Both views have led people gradually to extend treatment once reserved for mankind to other species.

But when everyday lives are measured against such principles, they are fraught with contradictions. Those who would never dream of caging their cats and dogs guzzle bacon and eggs from ghastly factory farms. The abattoir and the cattle truck are secret places safely hidden from the meat-eater’s gaze and the child’s story book. Plenty of people who denounce the fur-trade (much of which is from farmed animals) quite happily wear leather (also from farmed animals).

Perhaps the inconsistency is understandable. After hundreds of years of thinking about it, people cannot agree on a system of rights for each other, so the ground is bound to get shakier still when animals are included. The trouble is that confusion and contradiction open the way to the extremist. And because scientific research is remote from most people’s lives, it is particularly vulnerable to their campaigns.

In fact, science should be the last target, wherever you draw the boundaries of animal welfare. For one thing, there is rarely an alternative to using animals in research. If there were, scientists would grasp it, because animal research is expensive and encircled by regulations. Animal research is also for a higher purpose than a full belly or an elegant outfit. The world needs new medicines and surgical procedures just as it needs the unknowable fruits of pure research.

And science is, by and large, kind to its animals. The couple of million (mainly rats and mice) that die in Britain’s laboratories are far better looked- after and far more humanely killed than the billion or so (mainly chickens ) on Britain’s farms. Indeed, if Darley Oaks makes up its loss of guinea pigs with turkeys or dairy cows, you can be fairly sure animal welfare in Britain has just taken a step backwards.

With which of the following statements would the author most probably agree()

A. Even if they deplore the activitist’s use of intimidation and violence, animal lovers everywhere can sure rejoice today

B. Science does not deserve to be the target of protests, whatever you think of animal rights

C. Over the years something good has come from the campaign against the animal industry

D. It is a sensible move that Darley Oaks makes up its loss of guinea pigs with turkeys or dairy cows

单项选择题