In the absence of future tense,how does the English language express future time?
To make some new rules in English this question is very well. To make a sentence its role to use will/ shall for future but if u change that role then definitly English get some more roles.Lol
We make the simple Future tense by adding modal auxiliary "will" or "shall" with the first form of the verb.
Future of "I do" is "I will do" or "I shall do"