Put clauses in order

Explanation

Follow this content chain: 没考好→于是复习→一个月后进步. Establish the situation or cause before its response and result. Link words such as 于是, 因此 and 所以 to their antecedents. Reference passage: 小华这次考试没考好 于是他每天复习不懂的地方 一个月后成绩有了明显进步