帮我看看英语这几个题目的解答和详细解释？

Question

3. Some of the votes [ seem ] to have been miscounted. 
 (seem
 / seems)
5. Everyone selected to serve on this jury [ has ] to be willing to give up a lot of time. 
 (have / 
has)

9. Some of the grain [ appear ] to be contaminated. 
 (appear / 
appears
)10. Three-quarters of the students [ are ] against the tuition hike. (
is / 
are)
 
 11. Three-quarters of the student body [ is ] against the tuition hike. (
is / 
are)
 
 12. A high percentage of the population [ is ] voting for the new school. (
is / 
are
) 
 13. A high percentage of the people [ was ] voting for the new school. (
was / 
were
)首先我不知道我做的对不对 帮我看一下，第10题和第11题有什么区别吗， 第3题和第9题，some of 后面跟单数或者复数后面跟复数还是单数啊？
还有12和13的区别，我都混了，有谁知道帮忙详细的讲解一下谢谢啦

Answer 1

10题：students 是复数，所以谓语用are,
11题：student body是指全体学生，所以谓数用单数，is
3题：votes 是可数名词的复数，所以后面跟复数
9题：grain,谷物或粮食，是不可能名词，所以后面跟单数
12题：很高的比例投票了新学校。
13题：很大一部分人都投票了新学校

Answer 2

10.三分之一的学生，11.学生身体的三分之一
3.正确，9.应该是appears，grain是不可数名词

Answer 3

最后一道题应该是were
当名词是单数时，动词加s
当名词是复数是，动词不加s

Answer 4

分数以及名词单复数的区别

Answer 5

一些选票[似乎]已经数错