Not just "The car was washed." Use the passive to distance yourself from opinion or to describe processes.
To achieve an IELTS band 6.5 or higher, candidates must move beyond basic sentences and demonstrate "Grammatical Range and Accuracy." While a Band 6 candidate can use complex language with some errors, a Band 7+ candidate must produce . Essential Grammar Checklist for High Bands ielts grammar for bands 6.5 and above pdf
To achieve a Band 6.5 or above in IELTS, you must demonstrate a mix of "Grammatical Range" and "Accuracy." At this level, examiners are looking for your ability to use complex structures with high control. PrepGuru Academy Not just "The car was washed
You need mixed conditionals and inverted conditionals. ielts grammar for bands 6.5 and above pdf