英语高手请进!语法题,连词、介词短语,谢谢.1

英语高手请进!语法题,连词、介词短语,谢谢.1
首先在这里先说明一下情况,因为我的错题是考试的历年真题来的.同时这次的考试对我来说很重要,希望各位前辈能够帮助我,谨慎作答,因为我会完全相信你们的答案的!谢谢!（题目比较多,如果越详细,解释越明白.我会最后提高财富值的）谢谢!
麻烦每个选项分析,最重要给我做选择题的思路,觉得有必要的时候麻烦解析句意.谢谢
1.The house is well decorated______thedisarrangement of a few photos.
A.except B.besides C.except for D.in addition to
--我选了B,答案选C
2.I continued to study______thediscouragement I had received.
A.despiteof B.despite C.in spite D.in spite that
--我选了D,答案选B
3.Theory is based on practiceand______serves and guides practice.
A.in turn B.by turns C.taking turns D.in return
--我选了B,答案选A
4.How to dispose______the nuclear waste isa pressing problem for scientists and politicians alike.
A.out B.of C.on D.after
--我选了C,答案选B
5.They can’t rule_______the possibilitythat he was dead.
A.out B.of C.off D.from
--我选了B,答案选A
6.He was not an easy grader;we used tocomplain about his grasding standards,usually____.