粪便中出现夏科-雷登结晶常见于（）
A.过敏性肠炎
B.胃肠道出血
C.阿米巴痢疾
D.钩虫病
E.消化不良性腹泻
参考答案：A, C, D
There ______ a park near our school since two years ago. [ ]
A. is
B. was
C. has been
D. will be
以下哪个时期用药不当最容易引起胎儿畸形
A．孕前期B．孕早期C．孕中期D．孕后期E．哺乳期
