降钙素是一种多肽类激素，临床上用于治疗骨质疏松症等。人的降钙素活性很低，半衰期较短。某科研机构为了研发一种活性高、半衰期长的新型降钙
MnO2 MnO2 △ △ △ 2H2O2=2H2O+O2 2KClO3=2KCl+3O2 2HgO=2Hg+O2 2Na2O2+2CO2=2Na2CO3+O2， 现要制备等量的O2，则转移的电子数之比为
已知平面向量满足：，，且，则向量的坐标为 ______________.
Who is ___ the school? A. in the charge of B. in charge of C.on charge of D.in charge of
—My computer ____start, no matter how hard I try. —It might have crashed. A. won't B. shouldn't C. mustn't D. wouldn't
某地小学一年级语文教材删掉古诗引来不少质疑声，有网友感叹，“长大了，我才后悔小时候没多背几篇古文”。“去中国化”是很悲哀的，应该把经
