I治疗分化型甲状腺癌转移灶重复治疗两疗程一般应间隔（）。
A.1个月以上
B.2个月以上
C.3个月以上
D.4个月以上
E.6个月以上
参考答案：C
宣纸是中国文房四宝之一，其制作工艺被列入我国首批非物质文化遗产名录。下列关 于宣纸的传统制作工序中，主要发生化学变化的是
It was very difficult to rescue the drowning boy in the sea. One moment the rescue workers ____him
but the next moment they _____. [ ]
A. caught sight of; lost
B. caught the sight of; lost his sight
C. caught sight of; lost sight of him
D. caught the sight of; lost their sight of him
