搜题请搜索小程序“爱下问搜题”
问题 选择题

Maria has to baby-sit. That’s______ she can't come with us.

A．why

B．ho

C．when

D．what

答案

答案：A

单项选择题

Suppose that the demand curve for soybeans shifts such that the equilibrium price of soybeans decreases 58 percent. At the new equilibrium price, the quantity that soybean suppliers are willing to provide decreases by 3 percent. Which of the following most accurately describes the elasticity of supply for soybeans Elasticity of supplyRelative elasticity（）

A. -0.05 Elastic

B. +0.05 Inelastic

C. +19.33 Inelastic
查看答案
选择题

下列指定粒子的个数比为1∶2的是（  ）

A．Be2＋中的质子和电子

B．中的质子和中子

C．NaHCO3中的阳离子和阴离子

D．Na2O2中的阴离子和阳离子
查看答案