读句子，写出正确的国家名。

1. It's north of the U. S.. It has Niagara Falls.  __________________

2. It's west of China. It has a king or a queen.  __________________

3. It's east of China. It has Statue of Liberty.  __________________

4. It's flag is red, and it has five yellow stars.  __________________

再生障碍性贫血出血症状的原因，下列哪项是错误的：（）

A.毛细血管脆性增加

B.血小板减少

C.血小板功能不良

D.纤溶活动增强

E.血块收缩不良