（）适用于方形、马眼形、滴水形等宝石琢型，能使宝石镶嵌稳固。
参考答案：包角镶
Last week, only two people came to look at the house,________wanted to buy it. [ ]
A. none of them
B. both of them
C. none of whom
D. neither of whom
流脑病人病后在体内明显升高但确切功能不清楚的免疫球蛋白是（）。
A.IgA
B.IgG
C.IgE
D.IgD
E.IgM
