土地具有数量有限，稀缺和（）等特征。
A.不可替代
B.难以替代
C.可以替代
D.以上都不对
参考答案：A
对留置导尿患者的指导要点有哪些？
Every Monday morning, students in our school would stand at attention, watching the national flag ______.
A．raising
B．rising
C．being risen
D．being raised
