Tenses in reported speech

• When you use a reporting verb in the past tense you must change the verb tense used by the other person:

Present simple - past simple (The report found that 90% of participants agreed with…)

Present perfect - past perfect (…found that 27% of the patients had responded favourably…)

Past simple - past simple or past perfect (…found that most students planned / had planned their semesters…)

Can - could; will - would, may - might