蒸馒头、炸油条时常用到一种白色物质,它既能中和发酵过程产生的酸,又能引起发泡 作用,这种白色物质是
Sarah, hurry up, I'm afraid you won't have time to ____ before the party. A. get changed B. get change C. get changing D. get to change
某物体做直线运动,物体的速度—时间图线如图2-6-6所示.若初速度的大小为v0,末速度的大小为vt,则在时间t1内物体的平均速度( ) 图2-6-6 A.等
设P是椭圆+y2=1(a>1)短轴的一个端点,Q为椭圆上的一个动点,求|PQ|的最大值.
新疆瓜果特甜的主要原因是 A.气温高,降水丰富 B.云量少,日照多,气温日较差大 C.沙性土壤肥沃
在如图1所示的电路中,D1和D2是两个完全相同的灯泡,其额定电压在数值上约等于电源电动势,电源内电阻可以忽略不计,L是一个自身电阻可以忽略不
School phobia is a type of illness which causes students to be afraid to go to school.This condition is most commonly seen in children, typically between the ages of 8-13, and it can be very upsetti
设全集U={x|-2≤x≤2,x∈Z},A={x|x2-2x=0},B={-2,0}.求∁UA,∁UB.