Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.

[EX Q]: Context: In the Night Garden In a magical forest, colourful characters have adventures. A mysterious tide of water appears suddenly next to Igglepiggle. He discovers that he can control it by moving his feet. Excited, he takes it to Makka Pakka who finds it very useful indeed. Children Under 5 Today on BBC2 from 11:05am to 11:35am Last of the Summer Wine To relax, Howard tries a simple trick to change his appearance enough to fool even Pearl. But he soon discovers that taking over someone else's identity can be equally dangerous. Comedy Sitcoms Today on G.O.L.D. from 12:40pm to 1: 20pm The Secret Circle Cassie is an orphaned teenager who discovers that not only is she a witch but that she is also the key that will unlock a centuries-old battle between good and evil. When Cassie accepts a cute boy's invitation to the school dance, Adam struggles to control his anger. Today on Sky Living from 10:00pm to 11:00pm The Kid's Speech Eleven-year-olds, Reggie and William, and 14-year-old Bethan, are determined to improve their speech. Along with their parents, they start a unique course at the Michael Palin Centre for Stammering children. Over two weeks, they open up about their fears and frustrations. Documentary Today on BBC1 London from 10:35pm to 11:25pm 
 Question: Which play can be used to inspire children who are afraid to speak in public?
[EX A]: the kid's speech.

[EX Q]: Context: Weathering changes solid rock into sediments. Sediments are different sizes of rock particles. Boulders are sedi- ments; so is gravel. At the other end, silt and clay are also sediments. Weathering causes rocks at the Earths surface to change form. The new minerals that form are stable at the Earths surface. It takes a long time for a rock or mountain to weather. But a road can do so much more quickly. If you live in a part of the world that has cold winters, you may only have to wait one year to see a new road start to weather (Figure Mechanical weathering breaks rock into smaller pieces. These smaller pieces are just like the bigger rock; they are just smaller! The rock has broken without changing its composition. The smaller pieces have the same minerals in the same proportions. You could use the expression a chip off the old block to describe mechanical weathering! The main agents of mechanical weathering are water, ice, and wind. Rocks can break apart into smaller pieces in many ways. Ice wedging is common where water goes above and below its freezing point (Figure 9.2). This can happen in winter in the mid-latitudes or in colder climates in summer. Ice wedging is common in mountainous regions. This is how ice wedging works. When liquid water changes into solid ice, it increases in volume. You see this when you fill an ice cube tray with water and put it in the freezer. The ice cubes go to a higher level in the tray than the water. You also may have seen this if you put a can of soda into the freezer so that it cools down quickly. If you leave the can in the freezer too long, the liquid expands so much that it bends or pops the can. (For the record, water is very unusual. Most substances get smaller when they change from a liquid to a solid.) Abrasion is another type of mechanical weathering. With abrasion, one rock bumps against another rock. Gravity causes abrasion as a rock tumbles down a slope. Moving water causes abrasion it moves rocks so that they bump against one another (Figure 9.3). Strong winds cause abrasion by blasting sand against rock surfaces. Finally, the ice in glaciers cause abrasion. Pieces of rock embedded in ice at the bottom of a glacier scrape against the rock below. If you have ever collected beach glass or pebbles from a stream, you have witnessed the work of abrasion. Sometimes biological elements cause mechanical weathering. This can happen slowly. A plants roots grow into a crack in rock. As the roots grow larger, they wedge open the crack. Burrowing animals can also cause weathering. By digging for food or creating a hole to live in the animal may break apart rock. Today, human beings do a lot of mechanical weathering whenever we dig or blast into rock. This is common when we build homes, roads, and subways, or quarry stone for construction or other uses. Mechanical weathering increases the rate of chemical weathering. As rock breaks into smaller pieces, the surface area of the pieces increases. With more surfaces exposed, there are more places for chemical weathering to occur. Lets say you wanted to make some hot chocolate on a cold day. It would be hard to get a big chunk of chocolate to dissolve in your milk or hot water. Maybe you could make hot chocolate from some smaller pieces like chocolate chips, but it is much easier to add a powder to your milk. This is because the smaller the pieces are, the more surface area they have. Smaller pieces dissolve more easily. Chemical weathering is different than mechanical weathering. The minerals in the rock change. The rock changes composition and becomes a different type of rock. Most minerals form at high pressure or high temperatures deep within Earth. But at Earths surface, temperatures and pressures are much lower. Minerals that were stable deeper in the crust are not stable at the surface. Thats why chemical weathering happens. Minerals that formed at higher temperature and pressure change into minerals that are stable at the surface. Chemical weathering is important. It 
 Question: type of weathering that changes the minerals in rock
[EX A]: chemical weathering

[EX Q]: Context: Can storms in Africa cause asthma in the Caribbean ? Islanders point to the desert insects that land on beaches after a 5,000-kilometer flight across the Atlantic. If they can use winds to get from one continent to another, so can clouds of dust that carry disease. Scientists think that as Africa becomes drier, dust from expanding deserts is being blown away into Caribbean islands. A study in Barbados shows that asthma has increased 17 times since Africa's drought began in 1973. Other forms of life are suffering, too. Among them are the Caribbean's famous coral reefs( ), which began dying in large numbers in the 1900s. Eugene Shinn of the U.S. Geiological Sudrvey(USGS) in Florida went to the virgin Islands to study the reefs. The tests he and his colleagues carried out showed that the coral was dying of disease caused by Africa microbes from across the ocean. William Sprigg of the University of Arizona is studying the problem as part of a major UN project. He says that dust is causing problems in the U.S., too. "We are just beginning to collect the evidence of airborne dust influences on human health," he toldThe Washington Post. 
 Question: Where does the dust talked about in this passage come from?
[EX A]:
africa.