偏正关系句群: main-and-subordinate groups (转折, 因果, 让步…)
【高148】句群 / sentence groups (偏正关系)
Tone colorsā tone 1á tone 2ǎ tone 3à tone 4a neutral
In a 偏正关系句群 one sentence carries the point (正) and the others give it its condition, cause, purpose, contrast, hypothesis or concession (偏). Six types: 条件 (只有这样……), 因果 (因此), 目的 (这样做是为了……), 转折 (然而), 假设 (倘若……) and 让步 (即使这样). It is the group of sentences that repeats from sentence to sentence what the 复句 of hsk3 to hsk6 do inside one sentence (因为……所以……, 倘若……就……, 即使……也……).
Where is the point? In a 转折 it is the sentence after 但是 or 然而. The standard (高148) quotes a passage about two young people: 不少人热情地歌颂了他们的反抗和爱情，但是鲁迅先生以敏锐的目光看到了这种反抗和爱情中所包含的悲剧因素. Many celebrated them, but the point is what Lu Xun saw, the tragic element. In a 因果 the main sentence can come first or last (活动取消了。因为报名的人太少。). In a 让步 it follows the concession (天气可能会不太好。即使这样，我们也要按时出发。).
Practical rules: do not sum up a group by its first sentence; put the connective on the sentence that needs it, not on all of them; pick up a concession cut off by a full stop with 即使这样, never with 但是. Coordinate groups, where no sentence dominates, are in hsk7-g80. Register: written and speeches.
Examples
活动取消了。因为报名的人太少。
Huódòng qǔxiāo le. Yīnwèi bàomíng de rén tài shǎo.The event has been cancelled. Too few people signed up.
大家都以为他会拒绝。然而，他第二天就答应了。
Dàjiā dōu yǐwéi tā huì jùjué. Ránér, tā dìèr tiān jiù dāying le.Everyone thought he would refuse. Yet the next day he agreed.
也许明天会下雨。倘若真是这样，毕业典礼就改在礼堂举行。
Yěxǔ míngtiān huì xià yǔ. Tǎngruò zhēn shì zhèyàng, bìyè diǎnlǐ jiù gǎi zài lǐtáng jǔxíng.It may rain tomorrow. If so, the graduation ceremony will be held in the hall.
天气可能会不太好。即使这样，我们也要按时出发。
Tiānqì kěnéng huì bú tài hǎo. Jíshǐ zhèyàng, wǒmen yě yào ànshí chūfā.The weather may not be great. Even so, we'll set off on time.
你得亲自去看一看。只有这样，你才会明白他们的难处。
Nǐ děi qīnzì qù kàn yi kàn. Zhǐyǒu zhèyàng, nǐ cái huì míngbai tāmen de nánchu.You have to go and see for yourself. Only that way will you understand their difficulties.
学院把答辩提前了一周。这样做，是为了让大家有充足的时间修改论文。
Xuéyuàn bǎ dábiàn tíqián le yì zhōu. Zhèyàng zuò, shì wèile ràng dàjiā yǒu chōngzú de shíjiān xiūgǎi lùnwén.The college moved the defences forward by a week. It did so to give everyone enough time to revise their theses.
Common mistakes
✗ 即使天气不好。我们也要去。 → ✓ 天气可能不太好。即使这样，我们也要去。 (a concession cut off by a full stop is picked up with 即使这样; 即使 cannot stand alone before a full stop).
✗ 即使这样，但是我们也要去。 → ✓ 即使这样，我们也要去。 (a concession calls for 也, never 但是).
✗ summing up "大家都以为他会拒绝。然而，他第二天就答应了。" as "he refuses" → the point of a 转折句群 is the sentence after 然而: he agreed.