关于only 和the only的问题（2001－June－2－10）

unclekin

关于only 和the only的问题（2001－June－2－10）
    

前面lawyer的逻辑总结说了only和 the only的问题。2001年6月的这道题的the only的用法似乎和example里的the only way to不相同，但理解是否也应是一样的，即the only 后面的一律是充分条件？谢谢!

题目

2001年6月第二section 第10题

Although
the charter of Westside School states that the students body must
include some students with special educational needs, no students with
learning disabilities have yet enrolled in the school.  Therefore, the
school currently is in violation of its charter.

a. All students with learning disabilities have special educational needs.
b. The school currently has no students with learning disabilities.
c. The school should enroll students with special education needs.
d. The only students with special educational need are studetns with learning disabilities.
e. the school's charter cannot be modified in order to avoid its being violated.

答
案是D。由于charter -> special needs -> learning disabilities,
按照contrapositive，才有的conclusion 是违反charter。答案A是 learning
disabilities－>special needs，所以不对。可是D如果按照一般的only
解释，即only后面是必要条件，则也不对。是不是如果是the only后面就是充分条件？谢谢。

mengkez

b为什么不对呢、还有charter -> special needs -> learning disabilities这个怎么推的？谢谢！

isabellaL

charter -> special needs -> learning disabilities这么推的：

charter说必须enroll special needs students，现状没有录取learning disability students,所以只有special needs完全等于learning disability才算violation,正好是D说的。

提干缺的是enroll learning disability等同于special educational needs的桥梁，d正好补上了。b是提干的简单重复