下载APP
举一反三
【单选题】New Technique Promises Earlier Cancer Detection A new technique could revolutionize the early detection of cancer, giving sufferers a greater chance of beating the disease, American scientists said. R...
A.
before
B.
after
C.
although
D.
near
【单选题】宝石在正交偏光镜下出现异常消光的原因是
A.
均质体宝石中出现异常双折射
B.
由于应力作用或类质同象置换，使晶格产生了不均匀性
C.
宝石内部包裹体和裂隙过多
D.
以上选项均正确