There are 55 students in my class

There are 55 students in my class
There are 55 students in my class and 41 of them use weibo very often.That means about-----of your classmates are weibo users,right A two thirds B three quarters 3/4怎么算的?2,Put the tree in the hole-----it is stright A and B so C so that D such that D 可以吧.