HSK 6 Connectors & compound sentences
且不说 / 姑且不论 … 单 / 光 … 就 …
Not to mention… just… already… (且不说)
Structure 且不说/姑且不论 + larger point,单/光 + smaller point + 就 + conclusion
且不说 (qiě bù shuō) sets aside, for now, a larger point in order to rest on a smaller one that already suffices: 且不说路远,单是天气就够受的了 = "not to mention how far it is, the weather alone is already unbearable". The second clause is introduced by 单/光 ("just, merely") and closed with 就. The cultured variant is 姑且不论 / 姑且不说 (gūqiě bù lùn/shuō), which carries the "for the moment" sense of 姑且 and reads more like essay or news prose.
Examples
- 且不说路远,单是天气就够受的了。
Not to mention how far it is, the weather alone is already unbearable.
- 姑且不论质量如何,光是价格就让人望而却步。
Setting aside the question of quality, the price alone is enough to put one off.
- 且不说工程之大,单是预算就难以承担。
Not to mention the scale of the project, the budget alone is already hard to bear.
Levels are indicative: they follow the standard Chinese Grammar Wiki (AllSet Learning) progression, not an official HSK 3.0 mapping. We never assign levels by eye.