Tom and Dick are next door neighbor who work             小题1:___________

in the same office so they walked together to and from   小题2:___________

office. Some day as they were walking home together it   小题3:___________

sudden started to rain. Tom quickly opened his umbrella  小题4:___________

and said, "My wife surely has foresight(预见). She       小题5:___________

said this morning it would rain and tell me to carry my  小题6:___________

umbrella with me." Dick smiled and walked to him, said,  小题7:___________

"My wife has even great foresight. She told me not to    小题8:___________

carry an umbrella and as she knew you would certainly    小题9:___________

have with you."                                          小题10:___________

在1～18号元素中有三种元素X、Y、Z，已知最高价含氧酸的酸性存在如下关系：

HXO₄>H₂YO₄>H₃ZO₄，则Z元素的原子序数可能是（       ）

A．16

B．9

C．15

D．7