隔爆型电气设备的防爆关键在于()。
A、内部结构
B、外部结构
C、隔爆电路
D、隔爆外壳
参考答案:D
—What do you think of store shopping in the future?
—Personally, I think it will exist along with home shopping but ________.[ ]
A. will never replace
B. would never replace
C. will never be replaced
D. would never be replaced
下列不符合麻疹临床诊断病例的是()
A、麻疹疑似病例无标本,且无其他原因可以明确解释者;
B、出疹后3天内采集的血标本检测麻疹/风疹IgM抗体均为阴性,且无其他原因可以明确解释者;
C、麻疹疑似病例出疹后4-28天采集的血标本检测麻疹/风疹IgM抗体均为阴性,但与实验室诊断麻疹病例有明确流行病学联系,且无其他明确诊断者;
D、麻疹疑似病例出疹后4-28天采集的血标本麻疹IgM抗体阴性,但与实验室诊断麻疹病例无明确流行病学联系或有其他明确诊断者。