白勇语法第7章语法第50练习题，高手帮助

50.As rare as something becomes,be it a baseball card or a musical recording or a postage stamp,the more avidly it is sought by collectors

d.The rarer something becomes,like

e.The rarer something becomes,whether it is

答案的解释是whether is is X1 or X2 or X3是举例的一种表示方法.有这种方法吗?

Whether结构在这里应该是作为同位语来补充举例sth.的

即使作举例解，like代替such as举例是GMAT的一种经典错误，看到的第一眼就可以排除掉的那种