命题p:∃x∈R,x2+1≤0的否定是( ) A.¬p:∀x∈R,x2+1≥0 B. 发布时间:2017-04-18 10:51 │ 来源:www.tikuol.com 题型:选择题 问题: 命题p:∃x∈R,x2+1≤0的否定是( )A.¬p:∀x∈R,x2+1≥0B.¬p:∃x∈R,x2+1≥0C.¬p:∀x∈R,x2+1>0D.¬p:∃x∈R,x2+1>0
题型:选择题 It was Sunday and there were so many people in the streets that he found it difficult to _____ to the post office. [ ]A. make his way B. find his way C. feel his way D. lose his way 查看答案
题型:选择题 男,68岁,患“胃炎”20余年,因突然出现全腹剧烈疼痛,病人被动屈曲位,初体温正常,后出现最高体温38.5℃,脉搏110次/分,查体:腹式呼吸减弱,腹肌紧张不明显,全腹压痛、反跳痛,以上腹部为重;X线立位平片示小肠普遍胀气,并见小液气平面,膈下见游离气体。如暂时以非手术治疗为主,病人体位应是()A.仰卧位B.头低足高位C.平卧位D.半卧位E.无特殊要求 查看答案