问题
单项选择题
一项食管癌发病危险因素的成组病例对照研究结果表明，在150例病例组中80例有慢性胃灼热，而在300例对照组中20例有慢性胃灼热。
对照组慢性胃灼热的暴露率为( )
A．(80×280)/(20×70)
B．80/150
C．20/300
D．20/280
E．(80×100)/(350×70)
答案
参考答案：C
搜题请搜索小程序“爱下问搜题”
一项食管癌发病危险因素的成组病例对照研究结果表明，在150例病例组中80例有慢性胃灼热，而在300例对照组中20例有慢性胃灼热。
对照组慢性胃灼热的暴露率为( )
A．(80×280)/(20×70)
B．80/150
C．20/300
D．20/280
E．(80×100)/(350×70)
参考答案：C
| 完形填空。 | |||
| Have you ever planted a few trees on Tree Planting Day? Each year, millions of people, both 1 , plant a lot of trees. But this may not be the best way to make your home a 2 place. Last week we visited a park in Hebei. We were 3 to find most of the trees had been burned. The workers told us that the trees 4 soon after they were planted because they weren't watered well enough. 5 workers burned them and cleaned the place for 6 trees to be planted this year. 7 a card found in one of the dead trees, a student wrote:"I hope this tree will grow up with me to 8 the backbone (栋梁) of our country." The workers said that the survival (存活) of the trees was really more important than 9 trees were planted. Some people in Beijing now have a new idea that they can donate (损赠) some money and let professionals (专业人士) plant and 10 the trees. | |||
|