I found _____ hard to weigh this huge stone.[ ]
A. this
B. that
C. it
D. those
答案:C
黄海海战后,日本取得黄海海域制海权是由于
A.日本在黄海战役中取胜
B.北洋舰队全军覆没
C.北洋舰队损失过大
D.人为因素造成的
某医生随机抽取100名儿童,检测粪便蛔虫阳性率,得阳性率为20%,此阳性率的标准误为
A.4%B.0.4%C.0.04%D.0.2%E.1.6%