下列实验不能达到预期目的是()
A:用肥皂水区别硬水和软水
B:用碘水区别淀粉和蔗糖
C:用酚酞试液区别盐酸和食盐水
D:用点燃法区别聚乙烯和聚氯乙烯
在△ABC中,AB→=c→,AC→=b→.若点D满足BD→=2DC→,则AD→=( )
—Why don't you use your own knife?—Sorry, I've _____ it at home.
读“黄河水系图”,下列说法正确的是( )
① ____ A. ducks B. enjoy C. film【
② ____ A. pond B. cloud C. naughty2
③ ____ A. meat B. what C. hot dog