Put the modal verbs into the tenses.
Present simple: They must work harder.
Past simple: They………….work harder.
Present perfect simple: They…………….work harder.
Will-Future: They……………….work harder.
Present simple: We can help you in the garden.
Past simple: We…………….help you in the garden.
Present perfect simple: We…………………help you in the garden.
Will-Future: We………………..help you in the garden.
Present simple: She may invite friends.
Past simple: She………………….invite friends.
Present perfect simple: She………………….invite friends.
Will-Future: She…………………invite friends.