乳糖不耐受症是由于体内乳糖酶活性过低。( )
参考答案：对
________on the top of the hill is an ancient temple dating back to the 15th century. [ ]
A. Standing
B. Having stood
C. Being stood
D. Stand
控制汉坦病毒流行最重要的有效措施是（）
A.灭鼠
B.灭蚤
C.灭蚊
D.防蜱叮咬
E.使用特异性疫苗
