Itisestimatedthat，currently,about50，000speciesbecome_____everyyear．
设函数y=e^x+1，则y''=（）
It________asashocktorealizethatIwasnotaloneintheroom.
设A,B,C为三个随机事件,且P(A)=P(B)=P(C)=1/4,P(AB)=0,P(AC)=P(BC)=1/12,则A,B,C中恰有一个事件发生的概率为()
Tomplacedthebanknotes，_________thechangeandreceipts，backinthedrawer．
