5岁患儿,腹痛、呕吐、便血3天,双下肢踝关节有散在紫癜。最可能的诊断是()
A.肠套叠
B.梅克尔憩室
C.细菌性痢疾
D.过敏性紫癜
E.肠旋转不良
参考答案:D
We are taught that a business letter should be written in a formal style ________ in a personal style.[ ]
A. rather than
B. other than
C. better than
D. more than
下列哪些是组成电子雷管起爆网路系统的要件?()
A.欧姆表
B.铱钵表
C.数字密钥
D.导爆管雷管