射孔枪进行综合性能评价试验时，通常要求毛刺高度不得大于（）。
参考答案：2.5mm
下列结构中，不属于器官的是（ ）
A．牙
B．舌
C．血液
D．骨
It just isn't fair I was working as a waiter last month, my friends were lying on the beach. [ ]
A. whenever
B. though
C. while
D. for
