so that的倒装句So cold was the weather that we had to stay at home.天气太冷,我们只好呆在家里.So much did they eat that they could not move for the next hour.他们吃得太多了,一个小时都动弹不得.什么时候在形容词后接was 什么时候接did

第一句正常应该是the weather was so cold so that we had to stay at home.
第二句正常应该是they ate so much that they could not ……
看句子中实际的谓语动词应该是什么，如果有was,were, is,are等be动词时就把这些提前，如果是动词的各种形式，一般过去式把did提前，动词过去式变成一般形式；如果是一般将来时，将will提前；如果是现在完成时，将has或者have提前；等等。也就是说，你可以在倒装的时候就把它当成是要变成疑问句的形式来倒装，比如第二句里面，实际应该是they ate, 那倒装句就应该是did they eat; 同理如果原句是they have ate， 那倒装就应该是have they ate

这简单,既然是倒装,那么返回成正序就能知道谓语动词,倒装的时候就知道如何选择.
首先是倒装结构：So位于句首后跟形容词,然后是倒置的谓语动词,主语
第一句正序：The weather was so cold that we had to stay at home.
第二句正序：They ate so much that they could not move for the next hour.
其实可以发现,第一句谓语动词是be的过去式第二句是eat的过去式,故而倒装第一句was第二句did,那么如果出现完成时或者情态动词也是一样的,例如：正序 They had gone so far that they could not move any more.倒装：So far had they gone that they could not move any more.这里是谓语动词go的完成式,但与过去式不同倒装要倒置助动词had而不是did,故而这里有时态区分； 那么情态动词情况：正序 The weather will be so bad that they cancel the plan.倒装：So bad will the weather be that they cancel the plan.和过去式一样这里预见情态动词是将情态动词倒置.