女婴，出生时体重2300g（）。
A．足月儿
B．早产儿
C．低出生体重儿
D．正常体重儿
E．巨大儿
参考答案：C
已知代数式5+14x-21x2=-2，则代数式6x2-4x+5=______．
How does a coast radio station communicating by HF radio normally identify itself?（）
A.By its subscriber number
B.By its call sign
C.By its MMSI
D.By its MID
