慢性肾衰竭尿毒症期可有以下改变()
A．酸中毒
B．高血钙
C．高血钾
D．低磷
E．低血钾
参考答案：A, C
．Nowadays meteorologists can make good forecast for 3 or 5 days ．Perhaps soon they may be able to do that for a week or ____．
A．more behind
B．more ahead
C．less behind
D．less ahead
在一棵树中，哪一个节点没有前驱节点
A．分支节点
B．叶节点
C．树根节点
D．空节点
