题目

Every New Year's Eve in the past, we had breakfast at Aunt Dot's house.  My most vivid 41  of the meal was the centerpiece（中心装饰品）that Aunt Dot always   42   on her kitchen table-seven sets of salt and pepper shakers.  It wasn't until years later that I finally asked Aunt Dot about the unusual centerpiece. She was then 87 but she  43  invited us to the last breakfast of the year. I had   44  early that morning to help with the meal  45  ．Though weak, Aunt Dot was  46  stirring（搅拌）pancake batter(糊状物)as she  47  my question. You know I arrange下列关于晶体说法的正确组合是（　　）①分子晶体中都存在共价键②在晶体中只要有阳离子就一定有阴离子③金刚石、SiC、NaF、NaCl、H2O、H2S晶体的熔点依次降低④离子晶体中只有离子键没有共价键，分子晶体中肯定没有离子键⑤CaTiO3晶体中（晶胞结构如图所示）每个Ti4+和12个O2-紧邻⑥60gSi02中含Si-O键的个数为2NA⑦晶体中分子间作用力越大，分子越稳定⑧氯化钠熔化时离子键被破坏⑨124g P4含有P-P键的个数为4NA．A．①②③⑥B．①②④C．③⑤⑦D．③⑤⑧