从句可以充当主语、宾语、补语或附加说明。相同的 `that`, `if`, `because` 并不自动决定功能，必须看从句在上层结构中占据什么位置。
如何区分内容从句、关系从句和状语从句？为什么 because 回答原因，而 that 常把完整命题包装成名词性内容？
that 在内容从句中通常不充当内部成分；关系代词则在从句内部占位置。The authors argue that the effect is temporary.
that 从句填入 argue 的内容位置，回答作者主张什么。
The argument that the effect is temporary remains disputed.
同样的命题现在补充名词 argument 的内容，主句谓语是 remains。
The argument that the reviewers rejected was later revised.
这里 that 在从句中充当 rejected 的宾语，是关系从句；删除它会在内部留下宾语空位。
Whether the policy works depends on who implements it.
两个间接疑问从句分别作主语和介词补语，内部均采用陈述语序。
Although the estimate is imprecise, it is informative.
让步从句承认不利事实，主句仍坚持结论；逻辑不是因果，而是“尽管如此”。
Because the sample was small, the interval was wide.
because 明确作者把样本小作为区间宽的原因。
The interval was so wide that the estimate was difficult to interpret.
so...that 表达程度导致的结果，that 从句不是普通内容宾语。
What matters is not whether the result is significant but whether it is robust.
What matters 是融合关系结构作主语；两个 whether 分句构成 not...but... 的平行表语。
Although standardized tests provide comparable scores, they do not measure every educational outcome that matters. Schools may improve test performance because they teach the tested material more effectively, but they may also do so because they narrow the curriculum. Whether a score increase represents broader learning therefore depends on what changed inside the classroom. The central question is not simply whether scores rose but why they rose.
段落由让步、两种原因解释和两个间接疑问推进。that matters 是关系从句，内部缺少 matters 的主语；Whether... 则整体充当主语，不修饰某个先行词。
训练语境：学术科研
区分：the finding that surprised us 与 the finding that the effect disappeared。
前者是关系从句，that 在 surprised 中作主语；后者是内容从句，完整命题说明 finding 的内容，内部成分齐全。
训练语境：学术科研
修正：We do not know whether does the effect persist.
应写 whether the effect persists。间接疑问嵌入陈述句后使用主语在前的陈述语序，不保留直接问句的助动词倒装。
训练语境：学术科研
解释 while：While the model is simple, it captures the main pattern.
这里 while 表让步或对比，相当于“虽然”，不是同时发生。判断依据是两个命题的评价冲突，而非时间重叠。
训练语境：学术科研
Since the data were revised, the estimate has changed 有何潜在歧义？
since 可表时间起点“自数据修订以来”，也可表原因“因为数据被修订”。现在完成时支持时间解释，但语境仍可能让两者同时成立。
训练语境：学术科研
解释：The concern is that the measure captures income rather than wealth.
that 从句作系词后的表语内容，具体说明 concern 是什么。主句不是在断言该测量必然如此，而是在报告担忧的内容。
训练语境：学术科研
分析 unless：The estimate is biased unless selection is random.
unless P 近似 if not P：若选择不是随机的，估计有偏。它把随机选择设为避免偏差的条件，但语境未必证明这是唯一充分条件。
训练语境：真实生活
区分：I heard that she moved 与 I heard the news that she shared。
第一句 that 从句是 heard 的内容。第二句 that she shared 修饰 news，that 是 shared 的宾语；听到的是 news，不一定是“她搬家”。
训练语境：真实生活
修正：Can you tell me where is the station?
应写 where the station is。整个问句的倒装由 Can 承担，嵌入的 where 从句使用陈述语序。
训练语境：真实生活
解释差别：I left because I was tired 与 I left although I was tired。
because 把疲惫作为离开的原因；although 把疲惫设为与离开结论构成某种预期冲突的背景。连接词改变命题关系，不能只译词义。
训练语境：真实生活
分析：Whatever you decide will be fine.
Whatever you decide 整体作主语，表示“你决定的任何事情”。whatever 同时引入从句并在内部作 decide 的宾语。
The authors argue that the apparent stability of the measure should not be mistaken for conceptual clarity. They show that respondents who select the same option may be answering different questions, because some treat the scale as a measure of satisfaction while others treat it as a measure of obligation. What the study demonstrates, then, is that a survey item can be statistically reliable without being semantically stable.
argue that... 给出作者论点。show that... 给出证据和解释。What... is that... 总结研究证明的内容。that the apparent stability... 是 argue 的宾语从句。respondents who select the same option 中 who... 限定受访者。because... 从句解释为什么同选项不等于同理解。What the study demonstrates 是主语从句；that a survey item... 是表语从句。高阶语境：学术科研
第三句的主句谓语是什么？两个从句分别占据什么句法位置？
主句谓语是 is。What the study demonstrates 是主语从句，整体充当主语；that a survey item can be statistically reliable without being semantically stable 是表语从句，说明被证明的内容。
高阶语境：学术科研
解释 statistically reliable 与 semantically stable 的对比在论证中起什么作用。
前者说数据在统计上可能重复一致，后者说受访者是否在理解同一个意义。作者要说明：数字稳定不必然等于概念清楚，因此测量质量不能只看统计指标。
高阶语境：真实生活
请用 without being... 写一句生活例句，表达“一个评价可能很一致，但意思并不一致”。
可以写：A restaurant may receive consistently high ratings without being praised for the same reason by every customer. 一致的是评分，不一致的是评分背后的含义。
看到从句先问它在上层句子中占什么位置，再问连接词规定什么逻辑。不要因为都出现 that 就把它们归为同一种结构。