if y不等于3 and 3x/y is a prime integer greater than 2 ,which of the following must be ture
1. x=y
2. y=1
3. xand y are prime integers
A.none
B.1 only
C.2 only
D.3 only
E. 1 and 3
此外，请教一下这句话是什么意思：Sue drove 10 kilometers from home to work, and the ratio of distance driven from home to work was the same for Bill and Sue that day. | 
