①尊重创新,特别是青少年的创新精神和能力 ②提倡责任、奉献精神
③提倡不同民族和文化的平等交流 ④创新驱动发展战略的实施
A:①④
B:②③
C:①②
D:①②④
A: Excuse me. Is there a ____ near here?
B: Yes, there is.
A: Where is it?
B: It's ____the science museum.
A: Is it____
B: No, it isn't. Go straight to the first crossing and then turn ____
A: OK. I'll ____there. Thanks.
如图,在平面直角坐标系中,以O为圆心,适当长为半径画弧,交x袖于点M,交y轴于点N,再分别以点M、N为圆心,大于MN的长为半径画弧,两弧在第二象限交于点P.若点P的坐标为(2a,b+1),则a与b的数量关系为( )
经测定,由FeSO4和Fe2(SO4)3组成的混合物中,硫元素的质量分数为X%,则其混合物中铁元素的质量分数是( )