谁能解释一下这几道英语语法题1. This will please ___A the eyes B eyes C the

谁能解释一下这几道英语语法题
1. This will please ___
A the eyes B eyes C the eye D People's eyes
为什么选C
2.He was too much of a coward to tell the truth
为什么要加 a ? adj=of+a+n 吗?
3.We can let you have as many copies as you need
He can't carry parcels as heavy as these.
为什么不能改为we can let you have copies as many as you need 或者he can't carry as heavy parcels as these.