华支睾吸虫完成其生活史所必备的条件包括()
A.虫卵入水
B.水中有淡水螺、鱼和虾
C.有蚊虫叮咬
D.人们生活习惯(生食或半生食)不佳
E.人群易感性
参考答案:A, B, D, E
around the Water Cube, we were then taken to see the Bird’s Nest for the 2008 Olympic Games.[ ]
A. Having shown
B. To be shown
C. Having been shown
D. To show
BaSO4是典型的非晶形沉淀。