Pandy试验中,试管内出现灰白色云雾状浑浊,结果应判断为()
A.阴性(-)
B.可疑(±)
C.阳性(+)
D.阳性(++)
E.阳性(+++)
参考答案:C
At the Beijing Olympics, Bolt broke the 100-meter and 200-records and became the _____man in the world.
A.fastest
B.heaviest
C.tallest
D.slowest
When navigating using DGPS(Differential Global Positioning System)you may expect your position to be accurate to within a radius of().
A.10 meters
B.20 meters
C.50 meters
D.100 meters