Here is a selection of some web pages you can easily access from your mobile devices to practice some basic grammar:

Present Simple https://www.perfect-english-grammar.com/present-simple-exercise-7.html

Present Continuous https://www.perfect-english-grammar.com/present-continuous-exercise-5.html

Stative Verbs https://elblogdeidiomas.es/verbos-estaticos-en-ingles-stative-verbs/

Past Simple https://www.perfect-english-grammar.com/past-simple-exercise-8.html

Past Continuous https://www.perfect-english-grammar.com/past-continuous-exercise-1.html

Past Simple vs Past Continuous https://www.perfect-english-grammar.com/past-simple-past-continuous-exercise-1.html

Present Perfect https://www.perfect-english-grammar.com/present-perfect-exercise-4.html