易发生神经损伤的是（ ）
A．肱骨髁上骨折
B．股骨颈骨折
C．股骨干骨折
D．腓骨上段骨折
E．胫骨下1／3骨折
参考答案：A
If human beings had been a bit less greedy and cruel, more birds and animals ______ dying out. [ ]
A. ought to avoid
B. could have been avoided
C. should have avoided
D. might have avoided
开关量信号根据重要性可分为三类，其中不包括（）。
A.状态信号
B.状态信号
C.报警信号
D.告知信号
