However, no one has discovered any life in space yet. Why has no one from other planets sent us a message? Have they tried to send information to us? With so many stars in space, are we alone, or is there life on other planets in space?1. 请写出文中划线处“it”指代的内容。__...
and shop. But we already know this. What we have not yet understood is the way the tiny machines in front of us are changing our skeletons. Possibly altering not just the way we behave but even the very shape of our bodi...
A lot of people in England are crazy about football. During the football season whenever there is a big match, all the flags for local football teams, such as Liverpool and Newcastle, are hung outside every window, or even spread proudly on T-shirts or scarves. There is an atmosphere of...
In the past many studies placed too much emphasis on how animals are trained to learn. But recently more and more studies have focused on how animals equip themselves to learn. One study started with a school field trip to a pine forest where many pine cones were discovered, stripped (剥...
某油库工人许某，在上班进行输油作业过程中擅离职守，离开作业现场。储油罐装满后，汽油外溢，库区地面漂流大量汽油，空气中也形成大量可燃气体，因遇输电线火星；发生严重火灾，整个油库成为一片火海，给国家造成巨大经济损失，许某的行为构成：（）
B) discovered an extraordinary chemical C) altered its basic molecular composition D) found its evolutionary process sped up 54. What does Prof. McGeehan say about the recycling of plastic bottles? A) Manufacturers are implementing it on an increasingly larger scale. B) It generates huge...
There are many reasons, including the destruction of natural habitats, the introduction of species and the destruction of human prey. Many species, such as elephants, rhinos, wild tigers, giant pandas, birds and other animals, will face the fate of dinosaurs if they do not take protective ...
before biologists discovered the double helix structure of dna, alan turing, the mathematician who invented modern computing, proposed a bold theory of how animals got their patterns. turing hypothesized that as tissues develop, they pr...
Scientists have not discovered electromagnetic energy that behaves this way. Pet psychics also make several assumptions about animals' self-awareness and intelligence. We'll look at those in more detail next. Animal Emotions and Intelligence Many dogs appear to be happy while they are playing. ...
Finally, the parasite theory. Well, one thing that's typical of parasites is that their populations are not very large. Parasite populations have to stay within certain limits, because if there were too many parasites, they would kill off the host organisms they live on. But we're pretty ...