英语高手请进！！！英语语法题！谢谢 急急急！！

英语高手请进！！！英语语法题！谢谢 急急急！！
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，解释月明白。我会最后提高财富值的）谢谢！
1.________his lecture gives us a much betterunderstanding oflow-carbon econmy.
A．Tohavelistened to B.Having listened to
C.Listeningto D.Being listened to
----------à我选择了C，虽然答案做对了，但是不懂为什么这样选。对于其他答案也不知道为什么错。麻烦帮我分析一下各个答案。
B是现在分词的完成式，还是动名词的完成式？两者有做题时有什么区别吗？
D是动分词的被动式，还是动名词的被动式？两者有做题时有什么区别吗？
2.Soon，people hope ,the rains willreturn and ease the hardship ____the farmers.
A.facing B.faced C.faces D.faced with
-------à我选择了B
答案选A

3.That was one example of havingresponsibility_____I am on my own and of making my own decisions.
A.since that B.as that C.now that D.because of
----我选了B，答案选C

4.When they went into the shop and asked tolook at the engagement rings,the girl brought out the cheaper ones,_________shehad arranged with James.
A.those were what B.what was what C.which was what D.that was what
--我选了D，答案选C

5. The last decade_______tremendous changesin the means of transportation.
A.has witnessed B.waswitnessed C.witnessed D.is witnessed
我选了A,答案选C

6.The air will be fresh and clean if we_______rid of pollution.
A.will get B.will have got C.have got D.get
我选了D,答案选了C

7.Eat_____you like and leave the othersfor______comes in late.
A.any;who B.every;whoever
C.which ever;whoever D,either;whoever
--我选了D,答案选C