题目

阅读理解 The World Bank is warning that the West Africa Ebolaoutbreak could seriously harm the economies (经济)of Guinea, Liberia and Sierra Leoneunless action is taken quickly. World Bank President Jim Yong Kim spoke toreporters recently to discuss the effects of the Ebola spread. Our findings show that if the virus(病毒)continues to spread, the economic costto these countries could grow eight times by 2015. This would be a big catastropheto their already weak economies, said Kim. Mr. Kim says, saving lives and preventing newspread is most important. The bank has given $117-million fo对于相同条件下相同物质的量的O2和O3，下列说法中正确的是（　　）A．体积之比为1：1B．原子总数之比为2：3C．原子总数之比为1：1D．体积之比为2：3