预防感染需严格规范的操作是（）。
A.贫血、低蛋白血症
B.糖尿病、尿毒症
C.清创术
D.及时采取特异性免疫疗法
E.切断病原菌传播环节
参考答案：C
Evidence has been found through years of study ________ children's early sleeping problems are
likely to continue when they grow up. [ ]
A. why
B. how
C. whether
D. that
SS4，TGZ35A一4×1700／1020型整流装置中主桥、小桥元件弧RM（UDRM）为3000V时，断态（反向）重复峰值电流不大于（）（25℃）。
A、45mA
B、50mA
C、80mA
D、90mA
