是考查定语从句吗？该选in which case吗？

是考查定语从句吗？该选in which case吗？
 
有这样一道题，想想看，是用in which case还是in either case，还是in this case?
You can get there by plane or by boat, but in _________ case it’s very expensive.
A. which                        B. this                        C. any                        D. either http://yingyu.chazidian.com
【分析】此题应选D，其余三项均有可能误选。首先不能选A，因为句中有并列连词 but，这说明它是一个并列句，而in which case是用于引导一个定语从句；B也不能选择，因为 this 也是表示“确定”含义的，它与前面的 by plane or by boat 这种不确定性也不相符；选项C也不行，因为 any 是表示三者或三者以上的情形的，而 by plane or by boat 只有两种选择。答案选D，either 表示“两者中任意之一”。
请再看几个例子：
He may be busy, in which case I’ll call later. 他可能忙，如若如此，我以后再来拜访。
I may have to work late, in which case I’ll telephone. 我可能得晚点下班，那样我会打电话的。
My father may have to go into hospital, in which case he won’t be going on holiday. 我父亲可能需要住院，如果那样他就不去度假了。
Sometimes feta is very salty, in which case no salt needs to be added. 有时，羊奶干酪很咸。如果这样的话，就不必加盐了。
She may be late, in which case we ought to wait for her. 她可能迟到，因此我们应该等她。
比较：
He may be busy, and in this case I’ll call later. 他可能忙，如若如此，我以后再来拜访。
I may have to work late, and in this case l’ll telephone. 我可能得晚点下班，那样我会打电话的。
My father may have to go into hospital, and in this case won’t be going on holiday. 我父亲可能需要住院，如果那样他就不去度假了。
Sometimes feta is very salty, and in this case no salt needs to be added. 有时，羊奶干酪很咸。如果这样的话，就不必加盐了。
She may be late, and in this case we ought to wait for her. 她可能迟到，因此我们应该等她。