长期摄入低剂量铅后可引起慢性毒性,主要损害()。
A.神经系统
B.肝脏
C.造血系统
D.胃肠道
E.肾脏
参考答案:A, C, D, E
Tom eagerly finished up _____ was left of the chicken pie. [ ]
A. what
B. which
C. that
D. as
7342GPON正常的工作电压为()
A.-40.5V— -56V
B.110v
C.220v—250v