某地一项有关高血压的横断面研究表明：男性45～55岁组有高血压者占13％，女性占：15％。从而得出结论，该年龄组男性患高血压的危险性较女性小。该结论（）。
A.不正确，因为没有考虑到可能存在的队列的影响
B.不正确，因没区分发病率和患病率
C.不正确，因为未用率作性别间比较
D.正确
E.不正确，因为无对照组
参考答案：B
解析：该结论不正确，因没区分发病率和患病率，构成比不对。
| I watched as Dr. Ian Stead, the archaeologist in charge of the excavation, began carefully removing the peat with a clay modelling tool. X-rays taken through the box while it was at the hospital revealed ribs, backbone, arm bones and a skull (apparently with fractures). However, the bones showed up only faintly because acid in the peat had removed minerals from them. Using the X-rays, Stead started on what he thought might be a leg. By his side was Professor Frank Oldfield, of Liverpool University, an expert on peat who could identify vegetation from stems only a fraction of an inch long. "Similar bodies found in bogs in Denmark show signs of a violent death," Stead said. "It is essential for us to be able to distinguish between the plant fibres in peat and clothing or a piece of rope which might have been used to hang him." As Stead continued his gentle probing, a brown leathery limb began to materialize amidst the peat; but not until most of it was exposed could he and Robert Connolly, a physical anthropologist at Liverpool University, decide that it was an arm. Beside it was a small piece of animal fur — perhaps the remains of clothing. Following the forearm down into the peat, Stead found a brown shiny object and then, close by, two more. Seen under a magnifying glass, he suddenly realized they were fingernails— "beautifully manicured and without a scratch on them," he said. "Most people at this time in the Iron Age were farmers; but with fingernails like that, this person can’t have been. He might have been a priest or an aristocrat." Especially delicate work was required to reveal the head. On the third day, curly sideburns appeared and, shortly afterwards, a moustache. At first it seemed that the man had been balding but gradually he was seen to have close-cropped hair, about an inch or two long. "This information about his hairstyle is unique. We have no other information about what Britons looked like before the Roman invasion except for three small plaques showing Celts with drooping moustaches and shaven chins." The crucial clue showing how the man died had already been revealed, close to his neck, but it looked just like another innocent heather root. It was not recognized until two days later, when Margaret McCord, a senior conservation officer, found the same root at the back of his neck and, cleaning it carefully, saw its twisted texture. "He’s been garr0tted." She declared. The root was a length of twisted sinew, the thickness of a p string. A slip knot at the back shows how it was tightened round the neck. "A large discoloration on the left shoulder suggests a bruise and possibly a violent struggle," Stead said. |
Why did the researchers think the man was possibly a priest
A．(A) He had closely-cropped hair.
B．(B) His coat was fur-lined.
C．(C) He had a drooping moustache and shaven chin.
D．(D) His fingernails were well looked after.