一种筛检乳腺癌的试验应用于经病理检查证实患有乳腺癌的400例妇女和未患乳腺癌的400例妇女结果患癌组有100例阳性，未患癌组有50例阳性该试验能将实际无病按此标准正确判为阴性的能力是（）。
A.100/400=0.25
B.350/400=0.87
C.100/150=0.67
D.100/300=0.33
E.50/400=0.125
参考答案：B
| 基本语法选择合适的介词填空 | |
2. We left Hang Zhou ________the afternoon of October 15. 3. He called me__________ Sunday morning. 4. He had an accident________12 o’clock last Sunday. 5. They arrived________ this time yesterday. 6. My daughter was born ______ Julyl961. 7. The First World war broke out ______ 1941 and ended_____1918. |