乙状结肠扭转多见于
A．青壮年B．老年女性C．老年男性D．成年E．儿童
参考答案：C
I ______ able to sing any song but this one. [ ]
A. may
B. can
C. am
D. would
面先露的指示点是
A．枕骨B．颏骨C．骶骨D．臀部E．肩胛骨
