Littre疝是指嵌顿的疝内容物是（）
A．小肠憩室
B．大网膜
C．单个小肠肠袢
D．部分小肠肠壁
E．多个小肠肠袢
参考答案：A
Children are _____ to meet with setbacks (挫折) as they grow up, so their parents don't have to worry about it.[ ]
A. possible
B. due
C. necessary
D. bound
怎样保证液压管路装配后的密封性？
