①离子键没有方向性和饱和性，而共价键有方向性和饱和性

②配位键在形成时，是由成键双方各提供一个电子形成共用电子对

③金属键的实质是金属中的“自由电子”与金属阳离子形成的一种强烈的相互作用

④在冰晶体中，既有极性键、非极性键，又有氢键

⑤化合物NH₄Cl和CuSO₄•5H₂O都存在配位键

⑥NaCl、HF、CH₃CH₂OH、SO₂都易溶于水，但原因不完全相同．

C

     There are many festivals at our school. This month is October. In October there is a sports festival. We have the volleyball game and the basketball game during(在……期间) the festival. On October 15th，there is an English festival. On that day we have an English speech contest(演讲比赛)．On October 19th，we have a school trip. We go to Beijing with the teachers. On the last day of this month，there is a music festival. On that day we can enjoy beautiful music. It's really wonderful. Next month，there is an art festival. Students often display(展示) their pictures on that day.

“500年前，非洲人手里拿着象牙，欧洲人手里拿着《圣经》；500年后，欧洲人手里拿着象牙，非洲人手里拿着《圣经》。”这句话突出了近代以来世界殖民体系形成过程中的