通过统计调查得到的数据一般是观测数据。
参考答案：对
_________ you may have, you should gather your courage to face the challenge.
A．Whatever serious a problem
B．However serious a problem
C．However a serious problem
D．No matter how a serious problem
黏液癌最常见于（）。
A.血管壁
B.腹膜后
C.胃肠道
D.子宫
E.胆囊
