Forms 7a, 7c. Modals. To infinitive/ -ing form

 For practicing MODALS:

https://www.perfect-english-grammar.com/modal-verbs-of-ability-exercise-1.html;

https://www.perfect-english-grammar.com/modal-verbs-of-obligation-exercise-1.html;

https://www.perfect-english-grammar.com/modal-verbs-of-probability-exercise-2.html;

https://www.english-grammar.at/online_exercises/modal-verbs/m005-must-mustnt-neednt.htm;

https://www.tolearnenglish.com/exercises/exercise-english-2/exercise-english-87468.php;

https://www.tolearnenglish.com/exercises/exercise-english-2/exercise-english-97711.php;

https://www.englishgrammar.org/modal-auxiliary-verbs-exercise-6/;

https://www.englisch-hilfen.de/en/exercises/modals/form.htm;

https://www.myenglishpages.com/english/grammar-exercise-modals.php;

For practicing TO INFINITIVE/ - ING FORM:

https://www.really-learn-english.com/gerunds-and-infinitives-exercise-03.html

https://test-english.com/grammar-points/b1-b2/gerund-or-infinitive/2/;

https://www.perfect-english-grammar.com/gerunds-and-infinitives-exercise-1.html;

https://www.perfect-english-grammar.com/gerunds-and-infinitives-exercise-2.html;

https://learn-english-today.com/lessons/lesson_contents/exercises/gerund-infinitive_quiz1.html;

https://www.englishpage.com/gerunds/gerunds_infinitives_17.htm;

https://www.english-grammar.at/online_exercises/gerund-infinitive/gerund-infinitive6.htm.