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.

   Since 1964，colleges and universities in the U. S. have used Test of English as a Foreign Language，or TOEFL，to measure an international applicant's（申请人的）level of English. Universities in English-speaking European countries began using the International English Language Testing System，or IELTS，in 1989. These two tests have been the main choices for English ability testing in higher education admissions for international students until now.

In recent years，several companies have developed new English language tests that are low-cost and easy to use. And they aim to do more than just offer greater choices in the admissions process.

Founded in 2012, Duolingo creates software that teaches users many different languages, including English. In 2014, the company launched its own test of English language ability.

Jennifer Dewar works with Duolingo, helping to develop the test. She formerly worked as an admissions official at Washington University in St. Louis, Misouri. The school is one of hundreds of colleges, universities and other organizations in and outside the U. S. that now accept the test results for international admissions into their study programs.

Dewar says Duolingo created the test to lower the barriers to higher education for people worldwide, especially those in developing countries.

TOEFL and the IELTS cost about $ 300. They are given in a limited number of centers around the world. Some test-takers have to travel to take the tests, adding to the costs. Duolingo offers its test entirely over the Internet for $ 49. All test-takers need is access to a computer with a microphone，listening device and self-facing camera.

TOEFL，the IELTS and Duolingo measure a person's English reading，listening，speaking and writing abilities. But it takes about 45 minutes to complete a Duolingo test，compared to three or four hours for TOEFL or the IELTS. It is possible because Duolingo uses artificial intelligence（人工智能）to adapt to test-takers' abilities，using fewer questions to measure their skills.