Annealing is a way of making metal softer by heating it and then letting it cool very slowly. If metal is heated and then cooled very quickly , for example by dipping it in water , it will be very hard but also very brittle ---that is , It will break easily. Metal that has been annealed is soft but does not break as easily . It is possible to make metal as hard or as soft as is wished, by annealing it. The metal is heated, and allowed to cool slowly , for a certain length of time. The longer the heated metal takes to cool slowly , the softer it becomes . Annealing can also be used on other materials, such as glass. Why do people put hot metal in water ?   _ A) To make it hard B) To make it soft C) To make it cool D) To make it brittle
A


Scientists in Israel have discovered a new way to test for water pollution by "listening" to what the plants growing in water have to say. By shining a laser beam   on the tiny pieces of _ floating in the water,the researchers said they hear sound waves that tell them the type and amount of contamination   in the water. "It is a red light,telling us that something is beginning to go wrong with the quality of water," said Zvy Dubinsky,an aquatic biologist at Israel's Bar Ilan University."Algae is the first thing to be affected by a change in water quality.""The secret," he said,"is to measure the rate of photosynthesis   in the algae,meaning the plant's ability to transform light into energy." During photosynthesis,plants also release oxygen into the air. Dubinsky's technique is easy to perform because of the overabundance of algae in the planet's water.Most of the oxygen in the atmosphere comes from algae.A prototype tester that occupies about one square meter of a laboratory desktop,shoots a laser beam at water samples to stimulate photosynthesis in the algae.But not all of the laser's heat is used.Depending on the condition of the algae and the rate of photosynthesis,some of the heat is shot back into the water,creating sound waves,Dubinsky said.With a special underwater microphone,researchers are able to analyze the strength of the sound waves and determine the health of the algae and the condition of the surrounding water. "Algae suffering from lead poisoning,like waste discharged from battery and paint manufacturing plants,will produce a different sound than those suffering from lack of iron or exposure to other toxins," said researcher Yulia Pinchasov.She said that testing algae photosynthesis can determine water quality more accurately and easily than laborintensive methods now used like chemical and radioactive carbon testing. Why is the algae tested? A) Because it floats on the water. B) Because it can have photosynthesis. C) Because it is the first to be polluted. D) Because it can produce different sounds.
C


Q: Our site specializes in European cycling tours, Bike & Boat Tours, Road Bike Tours and now River Cruises   throughout Europe, Asia, and the Americas. We take great pride in offering you the best services and in providing you with a vacation that will be fondly remembered. Whether it is a European bike tour, river cruise, or one of many other cycling vacations, our staff will do everything to plan your dream holiday. Our bike tour prices are the lowest on the market and we've managed to keep them that way without sacrificing quality. We hope you'll let us take you on one of our many European cycling tours and now river cruise adventures! Bike & Boat Trips We have perhaps the largest online catalogue of well-established European bike and boat tours and sailing holidays. Luxury Boat Tours Take a Bike & Boat cycle tour on a luxury ship! A cycling tour in Europe with a beautiful boat by your side is not to be missed. Bike Europe and Beyond Bicycle touring in Europe and beyond -- cycle your next vacation almost anywhere in Europe from our carefully chosen catalogue of bike tours. Recently we have also added a few American bike tours as well as bike tours in Vietnam. Whether you cycle Europe with a standard bicycle or an e-bike (electrically assisted bicycle), one of our cycling tours is bound to be right for you. Road Bike Tours Cycle Europe and experience one of our great new European road bike tours! These cycle tours in Europe (and now one is in the New Zealand) are intended for the more experienced cyclist that is not afraid of the long distances through extremely beautiful countryside. River Cruises We now offer river cruises throughout the world's most famous waterways. Whether it is a European river or a river cruise in China, one of our cruises is certain to attract you. Which of the following require(s) certain cycling experience? A) Road Bike Tours. B) Bike & Boat Trips. C) Luxury Boat Tours. D) Bike Europe and Beyond.
A: A


*Question*
Hercule Poirot looked over the small gate which gave admission to Pine Crest. It was a modern nicely-built house. It was on a hill top, and the hill top was planted with a few sparse pines. It had a small neat garden and a large elderly man was watering with a big tin. Spence's hair was now grey all over. He had not shrunk much in girth , though. He stopped watering and looked at the visitor at the gate. Hercule Poirot stood there without moving. "God bless my soul," said Spence. "It must be. It can't be but it is. Yes, it must be Hercule Poirot!" "Aha," said Poirot, "you remember me. I'm grateful." Spence abandoned the watering can and came down to the gate. "What brings you down here?" "What has brought me to many places in my time," said Poirot, "and what once a good many years ago brought you to see me. Murder, Spence." "I'm done with murder since I retired," said Spence, "except in the case of weeds. Killing weeds is never easy as you think, something's always wrong. How did you know where to find me?" he asked as he opened the gate and Poirot passed through. "You sent me a Christmas card. It had your new address on it." "Ah yes, so I did. I'm old-fashioned, you know, I like to send round cards at Christmas time to a few old friends. I'm an old man now." "We both are." "Not much grey in your hair," said Spence. "I take care of my hair with a bottle," said Poirot. "There is no need to appear in public with grey hair unless you wish to do so. By the way, why have you come to live in Woodleigh Common?" "As a matter of fact, I came here to join forces with a sister of mine. She lost her husband, her children are married and living abroad. So I moved in here. Pensions don't go far nowadays, but we do comfortably living together." From the passage we can infer that they might   _   next. A) meet Spence's family B) discuss about a murder C) visit Spence's new home D) water the garden together
**Answer**

B