The elephant is another animal that lives in groups. An elephant herd usually has from twenty to forty members. The elephants in theherd depend on one another for help in time of trouble.
Dinosaurs were ancient species of reptiles. They lived on Earth for 160 million years. Some dinosaurs were as small as rabbits; others were enormous. Some ate meat, and others ate plants. They disappeared about 65 million years ago. Scientists believe that they starved to death. They think the climate changed quickly and caused many plants to die.
解析：此处lived/ disappeared;small/enormous; meat /plants均为反义词词组;
Recently, more airport officers have been shocked by the growth of animal smuggling. Sometimes, they find live turtles, lizards, frogs, and snakes in passengers' carry-on bags. Smugglers use several tricks to bring animals through airports. They put live snakes into film boxes and birds into tennis ball cans. Police even found an iguana taped to a man's chest. Not all animals are smuggled alive, however. Many die on the way. Animal body parts are also found. These include antlers, skins, dried organs, hooves, or feet.
A flying car society has many problems to solve. The first concerns safety. If there are no roads, what will stop people from crashing into each other? It is easy for a single car to travel, but what happens when there are thousands? Another issue is cost. At the moment, it costs several million dollars for one car. How can people afford to buy them? The third issue is fuel. At the moment, it costs several million dollars for one car. How can people afford to buy them? The third issue is fuel. There needs to be enough fuel to supply these cars. The fuel also needs to be less polluting than the kind we use now. Still, technology is advancing. It is likely that these problems will be solved in a few years. Then, dreams of quick and easy flight will be realities.
解析：此处文中用The first /Another /The third 结构上既避免了重复，又体现了语言的多样性;concerns、issue也是同义词替换;处处体现者语言的多样性;