Present tense
He understands the lesson
The lesson is understands by him.
Past tense.
He understood the lesson
The lesson was understood by him.
Present progessive
He is understanding the lesson
The lesson is being understood by him.
Past progressive
He was understanding the lesson
The lesson was being understood by him.
Future (will)
He will understand the lesson
The lesson will be understood by him.
Future (be going to)
He is going to understand the lesson
The lesson is going to be understood by him.
Present perfect
He has understood the lesson
The lesson ihas been understood by him.
Past perfect
He had understood the lesson
The lesson had been understood by him.
Modal verbs
He can understand the lesson
The lesson can be understood by him.
He must understand the lesson
The lesson must be understood by him.