AND前后两个名词的前面都要加the吗?

问题描述:

AND前后两个名词的前面都要加the吗?
比如:
As far as I know,the MS and (the) PhD are two graduate degrees.
据我所知,硕士和博士是两个研究生学位.

不一定不都加the的情况:
1.当两者为通类事物时只前面用the
2. 当一人带有两种称号时
比如Mr zhang is the teacher and friend of my