当PDA合并哪些心内畸形时，在未纠正心内畸形前不能闭合PDA A．VSD B．TOF

2007年5~6月，太湖流域发生了严重的水体富营养化现象，给当地居民的日常生活和生产带来极大的危害。据此回答1~2题。

1．湖泊比河流更易产生水体富营养化的原因主要是[ ]

A．湖泊水比较浅

B．湖水的更新周期长

C．湖泊的面积小

D．湖水的盐度高

2．水体富营养化对太湖造成的影响主要是[ ]

A．早期使湖水中水生植物大量减少

B．使鱼类因中毒而大量死亡

C．可能使太湖泥沙淤积，湖床抬高

D．使太湖及周边的生态环境恶化

已知等差数列{a_n }中，a_n≠0，且 a_n-1-a_n²+a_n+1=0，前（2n-1）项和S_2n-1=38，则n等于（　　）

A．10

B．19

C．20

D．38

将下列重要的国际组织以及总部所在地用线连接起来：

慢性心功能不全患者长期服用噻嗪类利尿剂，最常出现的不良反应

A．低钾血症
B．高钙血症
C．低钠血症
D．脱水症
E．氮质血症

Charles is working on a project and finds that one of his primary vendors is raising their costs for a key component of the product being produced by his project．In order to cover these costs，he______．

A．will ask management for a budget increase to cover the difference

B．will assume management reserve will cover the difference because this increase was out of his control

C．will use the cost change control process to obtain approval to use part of the contingency allowance

D．will go over budget and ask for forgiveness at the end of the project Charles