特殊运算符“Is Null”用于指定一个字段为( )。
A.空值
B.空字符串
C.缺省值
D.特殊值
参考答案:A
汉译英:“检验报告;卫生证书;替代证书”,正确的翻译为:( )
A.sanitary certificate;report Of findings;replacement certificateB.replacement certificate;report Of findings;sanitary certificateC.report Of findings;sanitary certificate;replacement certificateD.sanitary certificate;replacement certificate;report Of findings
A.密度
B.比热
C.沸点
D.颜色