Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.
Leeches are small wormlike creatures that live in water and suck the blood of animals and humans. In the past, though, leeches were commonly used in medicine to drain blood from people. Then advances in science led to other kinds of treatments, and leeches disappeared from the sick room. Now, however, they are making a comeback. Leeches are being used after operations for the reattachment of body parts, in the prevention of pain from arthritis, and in the treatment of heart disease. The use of leeches in medicine goes back at least 2,500 years. Doctors used them to treat the sick in ancient Egypt, India, Persia, and Greece. It was believed in those days that taking blood from patients helped to bring their bodies back into balance. This belief and the practice of draining blood with leeches continued through the ages, reaching a high point in early nineteenth century France. At that time. Parisian hospitals required as many as 6 million leeches a year for their patients.
By the middle of the nineteenth century, however, the practice of draining blood from patients was becoming less popular. With a better understanding of diseases and of the human body, doctors realized that taking blood from the patient (with or without leeches) was not always helpful and leeches made no real difference in many cases. By the twentieth century. doctors had completely abandoned the use of leeches to drain blood. But in 1985 Dr. Joseph Upton, a surgeon in Boston, Massachusetts, discovered a new use for them. Faced with a young patient whose ear had been bitten off by a dog, Upton successfully reattached the ear in a twelve-hour operation. However, within three days, the ear had turned black because blood could not move through it properly. During the operation, it had been fairly easy for Upton to reattach the arteries that brought blood to his patient's ear, since artery walls are thick and easy to see. However, since the veins that carry blood away from the ear are much smaller and hard to find. Upton had not been able to reattach enough of them. If something wasn't done quickly, the ear would not survive.
Luckily, Dr. Upton remembered an article he had read about research into the properties of leeches. Though the results of the research were stilt uncertain, Upton decided to take a chance. He bought some leeches from a laboratory and placed them on the boy's ear and they began to feed. The boy felt no pain because the mouths of leeches contain a natural painkiller. As the leeches sucked some of the extra blood out of the boy's ear, they added a special chemical to the blood so it would not harden and form clots and it would flow more easily. Within a few minutes, the boy's ear began to lose the terrible black color. The leeches had soon eaten enough and fell off. Several days later, after applying more leeches, the boy's ear was entirely pink and healthy. Other doctors then began to experiment with the use of leeches in the reattachment of other body parts, and finally. in 2004. the United States Food and Drug Administration approved the use of medicinal leeches in reconstructive surgery.
When Upton tried to reattach the ear for the patient,__________.
A.the patient's blood stopped running
B.he couldn't attach enough veins
C.the arteries were too small to attach
D.the patient ran out of blood
