Why are modals often tested in the Structure section of grammar?

Modals are frequently tested in the Structure section of grammar because they convey important nuances in communication, specifically relating to ability, permission, requests, obligations, advice, and expectations. For instance, using "can" indicates ability, "may" conveys permission, while "should" suggests advice. These distinctions are essential for effective communication, as they allow speakers to express varying degrees of certainty, necessity, and politeness.

By assessing one’s understanding of modals, the Structure section can gauge a learner's grasp of more complex grammatical concepts, as the use of modals significantly influences the meaning of sentences. Understanding these subtleties allows students to communicate more effectively and appropriately in different contexts and conversations.