A
Many common things around the house are very useful. For example, warm water can be used for cleaning. When salt is put 1 warm water, it can help ease a sore throat. Warm water can also be used to make an orange taste better. The secret is the warmth of the water. The fruit becomes sweeter, 2 the warm water lowers its level of sourness. Another example is 3 you can try a banana peel when your shoes look dirty. The tannin in the peel works like magic, making your shoes shiny and bright!
B
Not all inventions have been the result of a 4 (care) plan. In the 1940s, an American scientist, Percy Spencer, was trying to make a machine, with the hope that it 5 (use) radio waves to detect warplanes. One day, after the experiment, Spencer found that a chocolate bar in his pocket had melted. Spencer then placed some corn in front of the machine. Soon, the corn was popping everywhere. Thus, the microwave oven（微波炉）6（invent）by chance．
C
A group of large white birds with black faces appear in the sky. There are only about six hundred of them 7 (leave) in the world. These beautiful black-faced spoonbills are some of the world’s rarest birds. The birds 8 (fly) all the way from their summer home to this wetland, 9 they will spend the winter. Now, they circle and land. Many people are crowding by the lake and then begin to shoot them. Is this the end for the spoonbills? No. The people are bird-watchers, 10 (shoot) photographs.