下列各组烃的混合物，只要总质量一定，无论按什么比例混合，完全燃烧后生成的CO₂和H₂O都是恒量的是                               

某密闭容器中发生如下反应：X(g)＋3Y(g)2Z(g)；ΔH＜0。下图表示该反应的速率（v）随时间（t）变化的关系，t₂、t₃、t₅时刻外界条件有所改变，但都没有改变各物质的初始加入量。下列说法中正确的是(   )

下表反映了50年来科尔沁沙地重心移动的情况。据此回答题。
【小题1】从整体上看，科尔沁沙地重心的移动方向

A．向西北方向移动	B．向东北方向移动
C．向东南方向移动	D．向西南方向移动

【小题2】导致科尔沁草原沙化土地出现连片发展趋势的主要原因是

作为一个对自己的行为负责的人，应该（    ）

①对自己的行为可能产生的后果做出正确的判断   ②严格要求自己，对可能对他人、社会不利的行为坚决不去做

③遇到困难的话，逃之夭夭                                       ④做错事勇于承认错误，承担后果

   There are many wetlands（湿地） in China and some of them have become the world‘s important wetlands. The Chinese Yellow Sea Wetlands are among them. They are in Yancheng， Jiangsu Province. They are home for many different kinds of birds and animals. The world’s largest Milu Deer Nature Reserve（自然保护区） is in them. More than 700 milu deer live freely there. There are not many red-crowned cranes in the world， but every winter you can see some in the Red-crowned Cranes Nature Reserve in the Yellow Sea Wetlands.
   The temperature in the wetlands is usually neither too high nor too low. There is a lot of rain and sunshine， too. They are really good places for wildlife（野生生物）。 Offering food and home for some special kinds of animals and birds is not the only reason why we need to protect wetlands. Wetlands are important because they also prevent flood. But some people want to change the wetlands to make more space for farms and buildings. This means there will be less and less space for wildlife.
   Luckily， more and more people are beginning to realize the important of wetlands and wildlife. Every year， on February 2nd， many activities are held to tell people more about wetlands.
根据以上短文内容，然后从每题所给的四个选项中选择最佳选项。