Humans have been keeping animals as pets for tens of thousands of years, but Dr Jean-Loup Rault, an animal scientist at the University of Melbourne in Australia, believes new companions are coming: robot pets.

“Technology is moving very fast,” Rault told ABC News, “The Tamagotchi in the early 1990s was really the first robotic pet, and now Sony and other big companies have improved them a lot.”

This may not sit well with pet lovers. After all, who would choose a plastic toy over a lovely puppy? But Rault argues that the robotic kind has a lot going for it: “You don’t have to feed it, you don’t have to walk it, it won’t make a mess in your house, and you can go on a holiday without feeling guilty.” The technology also benefits those who are allergic to pets, short on space, or fearful of real animals.

It’s not clear whether robot pets can replace real ones. But studies do suggest that we can bond with these smart machines. People give their cars names and kids give their toy animals life stories. It’s the same with robots. When Sony stopped its repair service for its robot dog Aibo in March 2014, owners in Japan held funerals.

As an animal welfare researcher, Rault is concerned about how robotic pets could affect our attitudes towards live animals. “If we become used to a robotic companion that doesn’t need food, water or exercises, perhaps it will change how humans care about other living beings,” he said.

So are dogs and cats a thing of the past, as Rault predicts? For those who grew up with living and breathing pets, the mechanical kind might not do. But for our next generation who are in constant touch with smart technology, a future in which lovely pets needn’t have a heartbeat might not be a far-fetched dream.

   Would you buy a car that can release calming smells into the air when you are stuck in heavy traffic? Would you buy a robot that smells like a human being?

Many people have seen the 3-D computer-made environments of virtual reality（虚拟现实）. Now these virtual worlds will not just look and sound real. Researchers have created VR environments that even smell like the real ones. With the new technology, users open a virtual door and step into a new environment, like a rainforest. After they enter this virtual world, special equipment releases forest-like smells into the air to make the experience feel more real.

Suzanne Fisher-Murray said, “It is a really wonderful experience that you have because you’re exploring this environment and you have smells with it.”

In the United States, Smell-O-Vision was designed to provide smells during the showing of a movie. The Smell-O-Vision system was once popular in the 1960s. Now, Emanuela Maggioni says it is close to becoming popular again. “It connects emotions and memories with the sense of smell,” Maggioni said. “It is unbelievable what we can do with the technology.”

The uses of smell technology are not just limited to films and the performing arts. Researchers showed a computer program where users could imagine themselves driving a car. The system included a special smell-spraying machine. Dmitrijs Dmitrenko said, “We want to deliver the smell of lavender(薰衣草) every time the person drives over the speed limit. We choose lavender because it’s a very calming smell.”

Scientists are experimenting with smells instead of sounds or image-based alerts on telecommunications equipment. And businessmen have already used smells to influence people’s behavior. “Not only in stores, but also in other places you can create and stimulate(刺激) immediate purchase,” Maggioni said. “So you’re in a library and when you smell coffee you will unconsciously have the need to drink a coffee.”

   Onions make you cry, add flavor to food and win popularity for their medicinal benefits. Now the vegetable has another use—_____ green energy.

Anew system debuts（首次亮相）on Friday that _____ onion juice into electricity at Gills Onions, the largest fresh onion processor in the United States.

The Oxnard, California-based company _____ its new onion-fueled power to reduce its electric bill by $700,000 a year and _____ its annual greenhouse gas emissions by up to 30,000 tons.

The _____ ending to this green energy tale, however, started with another question: how to _____ onion waste.

“_____ we peel an onion, 35 to 40 percent of the onion comes off before we have a(n)_____ onion. That's the top, tail and skin around the onion, and _____ we can get to the meat,” said Steven Gill, co-owner of the 25-year-old company.

They used to pull the waste to the fields for compost（混合肥料）, but that turned out to be a tough ______. Ten years ago, Gill started looking at technology for a(n) _____, including microturbines（微型燃气轮机）.

“We ______ cutting the skins into pieces and extracting all the ______, which is very high in sugars, and bacteria love that stuff,” Gill said.

In the new system, bacteria ______ methane（甲烷）gas from the juice. The gas then goes to two 300 kilowatt fuel cells, creating ______ power for 460 homes. If everything goes smoothly, ______ are that the company will get 35 to 40 percent of its electricity from the on-site generator.

The company ______ $ 9. 5 million in the project and will receive $2. 7 million from Southern California Gas Co. _____ cutting its electric bill, the company will save $400,000 in costs and expects paybacks in the new future.

The onion grower now has a new ______: to be a zero-waste facility in the coming decade.

“We want to ______ it all the way through and make the full circle,” Gill said.