锤击沉桩时,当锤击高度已经达到规定最大值和每击贯入度小于或等于()mm时,应立即停锤。
A.1
B.2
C.3
参考答案:B
发热、感染和饥饿时易引发维生素D缺乏性手足搐搦症,其原因是()
A.神经肌肉兴奋性增高
B.组织细胞分解释放磷,使血磷升高,血钙下降
C.血糖下降
D.脑细胞代谢异常
E.代谢性酸中毒使血钙下降
I study in High School Affiliated to Southwest University. There are __________ students in our school. Nine ______________ of them are girls.
A.thousands of; hundred
B.thousand of; hundreds
C.thousand of; hundred
D.thousands of; hundreds