In the factory, there are 100 workers. About _____ of workers are girls. So forty workers are boys.
A：three fifth
B：three fifths
C：three tenth
下列标点运用正确的一项是（ ）
A．Ag2O+H2O2=2Ag+O2↑+H2O
B．3H2O2+Cr2（SO4）3+10KOH=2K2CrO4+3K2SO4+8H2O
根据“观察人的口腔上皮细胞实验”回答有关问题：
用一般光学显微镜观察生物的细胞与组织，下列叙述不正确的是( )
