有几道英语定语从句的不懂选呢.

有几道英语定语从句的不懂选呢.
1.Janet,_____ is in my class,is atalented singer and dancer.
a.the brother of hers b.the brother of whom
c.her brother d.whose brother
2.The company has developed a newlaptop computer ____ will make it attractive to students.
a.whose low costs b.the same low costs
c.such low costs d.such low costs as theirs
3.My sister,_____ at my house lastyear,is working as a receptionist at a clinic now.
a.as you met b.that you met c.you met whom d.whom you met
4.Thousands,_____ were from thesurrounding towns,came to watch the match.
a.of those many b.many of whom
c.many of those d.who of many
5.The vote was then taken,with thesame result ______.
a.like previously b.that was previously c.previously as d.as previously
6.There is a leather suitcase,_____is broken,in the storeroom.
a.the handle of which b.the handle of that
c.the handle ofits d.its handle
7.We met the man _____ onanimal-life has received worldwide recognition.
a.the book of whom b.whose book
c.the book of his d.whose book is
8.It was the only thing _____ underthe circumstances.
a.which I could do b.as I could do
c.I could do that d.that I could do
9.He returned with tobacco,matches,and _____ were needed.
a.those provisions as b.the same provisions as
c.such provisions as d.those provisions such as

1.d. whose brother(不能选B.因为不能特指)
2.a.whose low costs ( 新型手提电脑的低成本)
3. d. whom you met (先行词My sister指人, 在定从中作宾,故用whom引导定从)
4. b. many of whom ( Thousands 指人,数千人,因此用whom指代)
5. d. as previously(the same .as 固定搭配)
6. a.the handle of which(= the handle of the leather suitcase 皮箱的提手)
7. d. whose book is (用了is,定从才完整)
8. d. that I could do(先行词前有the only,定从只能用that引导)
9. c.such provisions as (such .as 固定搭配)
不懂可追问.
再问： 第三题为什么选whom 还有第四题为什么不用who of many 第五题完全看不懂什么意思- - 楼上两个人第七题都没加is也。为啥？
再答： 第四题: 表示其中的许多人 要用many of whom ,不能用 who of many(意思不通: 许多人中的谁) 第五题 句意: 然后进行了投票, 投票结果和前一次一样. with the same result as previously 和前一次一样的结果. 另更正: 第七题 是B
再问： 第七句的中文意思是什么呢？
再答： 我遇见了关于动物生活的书获得了世界声誉的那个人.