在表示某一事物发生的因果关系时，表示原因的连词写在表示原因的句子内，结果连词用来连接某一事物所引起的结果；可以是前因后果，也可以是前果后因。其关联词主要有because, since, as, for, on account of, on the ground of, as a result of, due to the fact that, result from, result in, so, therefore, thus, hence, accordingly, consequently, as a result, as a consequence, now that, in that, lead to等。因果关系需根据前后文的内容进行判断。完形填空中因果关系的考查主要在于关系词的选择，有些是文章中明显的因果关系，而有些是隐含的，需要自己去判断。

【真题回放1】These responses to extreme exercise，_____to swelling and soreness that peaks a day or two after the event and resolves a few days later, depending on the severity of the damage.

[A]contributing

[B]processing

[C]resulting

[D]leading

解析　本空根据句意是讲剧烈运动的这些反应，_____后为肿胀和疼痛，此处为明显的因果关系，应区分因果关系的不同固定搭配以及不同的使用语境, lead to（导致，引起）为固定搭配，故答案为[D]。[A]contributing, contribute to（有助于）与此处的语境不符；[B]processing, process to表示进程，无因果关系；[C]resulting表示因果关系，后跟介词in。(www.daowen.com)

【真题回放2】However, because these connections are made through effort and practice, scientists believe that intelligence can expand and fluctuate_____mental effort.

[A]according to

[B]regardless of

[C]apart from

[D]instead of

解析　从句为because引导的原因状语从句，该句指出，这些连接是通过努力和训练获得的（are made through effort and practice），其中用的是through（通过），是手段方式表隐性的因果关系，表达前果后因。主句指出，科学家们认为智力能够_____大脑训练来加强和波动（can expand and fluctuate_____mental effort）。两个句子的成分平行，因此空格处应该填入一个与through意思相近的词表达隐性的因果关系, according to（根据）表示隐性的因果关系，故答案为[A]。[B]regardless of（不管，不顾）表示让步关系；[C]apart from（除……之外）表示子集关系；[D]instead of（而不是……）表示对比关系。