血铅、汞是反映（）。
A.毒物所致病损的指标
B.中毒程度的指标
C.毒作用的指标
D.毒物吸收的指标
E.毒物在体内代谢的指标
参考答案：D
羊水检查时，计算脂肪细胞百分率应计数多少个细胞（）
A.20～50
B.50～100
C.100～200
D.200～500
E.500～800
Every year, a great many visitors come to visit the temple ____ the 12th century, ______ has brought a large income.
A．dating from ;which
B．dated from;which
C．which dates from ;that
D．which dated from ;which
