肠套叠的促发因素是（）
A.饮食改变
B.腹泻
C.病毒感染
D.肠息肉
E.以上都是
参考答案：E
It was ________ very rare find and the archaeologist who made ________ discovery said it was like unearthly a Mona Lisa.
A．a; the
B．the; the
C．the; a
D．a; a
诊断阶段
A．一核包囊B．滋养体C．二核包囊D．四核包囊E．滋养体和包囊
