一般临床上最为常用的毫针是
A．26～28号B．27～29号C．28～30号D．29～31号E．30～32号
参考答案：C
---- Who is it that is making so much noise upstairs?
---- ______ the students preparing for the New Year’s Party.
A．There are
B．They are
C．It is
D．That is
何为矿产质量？
