向50 g FeCl3的溶液中加入一小块钠，待反应完全后，过滤，得到仍有棕黄色的溶液45.9 g，则投入钠的质量为（ ） A.4.6 g B.4.1 g
如图所示，将凸透镜固定在光具座上某位置（图中未标出），点燃的蜡烛放在光具座上的a点，调节光屏的位置，在光屏上得到烛焰清晰缩小倒立的像．
张、李两家因承包鱼塘发生纠纷诉至法院。张家对法院一审不服，他可以（ ） A.上诉 B.经一审法院
下列有关金属腐蚀与保护的说法正确的是 A. 常温下，断开K时，若M溶液为浓硫酸，则铁发生化学腐蚀 B. 关闭K，若M为氯化钠，则铁极的电极反应式为O2+4e
The cause of his death __ his careless driving after too much wine. A. led to B. caused C. lay in D. resulted in
The Science Museum, _____ we visited during a recent trip to Britain, is one of London’s tourist attractions. A. which B. what C. that D. where
We dislike people ______ talk much but never do anything. A. whom B. which C. who D. whose
The dog _______for two months. Its _____ made us very sad. A. has been dead; died B. died; dead C. has been dead; death
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