呆小症的病因是幼年时()
A.糖皮质激素分泌过多
B.甲状腺功能不足
C.生长素分泌不足
D.食物中缺乏碘
E.食物中缺乏蛋白质
参考答案:B
下列多项式中,能运用公式法进行因式分解的是( )
A.-a2+b2
B.x2-2x+4
C.-4m2-9n2
D.x2+4y2
John was________to learn the news that he was rejected by the committee.[ ]
A.let down
B.put down
C.noted down
D.taken down