输血是感染HIV的重要途径，输血传播HIV的有效率估计为（）
A.>10%
B.>50%
C.>90%
参考答案：C
用适当的介词填空。
1. Look the hens.
2. I go school at 7:30 every morning.
3. Put your sweater. It's cold.
4. I want a pair shoes.
5. It's time lunch.
术后镇痛常见并发症有哪些？
