Parallel Actions: Future Continuous Tense expresses an action ongoing together with another action in the future. Another way to explain:
Future Continuous Tense is used when an action is ongoing while another action is taking place too. This second continuous action serves a time-indicator. It shows when the main action takes place. By introducing another ongoing action, we can show the period of time or dynamic point in time.
We’ll be studying tenses while (sometimes when) they are playing online games.
While they are playing online games, we’ll be studying tenses. (Pay attention to punctuation)
Interestingly, both the actions are ongoing in parallel with each other. It means that each action has equal rights to be used in Future Continuous. However, the one that goes after when, while, will be a time-indicator for the main action.
We’ll be studying tenses at 2 pm / while they are playing online games.
Also, it will be in Present Continuous (not Future Continuous) because of the influence of when or while.
Remember, a period / point in time can be literally time on a clock or another action. In this scenario, it is another continuous action.
Parallel Actions: Future Continuous with while / when / and
Note, we do not use future tenses after:
if / when / after/ before / as soon as / unless / until and their synonyms or synonymous expressions.
Instead, we use present tenses after these words to express a future action.
This is why:
We’ll be studying tenses while they are playing online games.
While they are playing online games, we’ll be studying tenses.
Let’s change this sentence and see how “while” affects it from the other side of the sentence. Compare:
While we are studying tenses, they will be playing online games.
While they are playing online games, we’ll be studying tenses.
Both the sentences basically mean the same, however, note how “while” affects the use of a future tense.
Both the actions are in parallel with each other and with equal rights, however, “while” disturbs equality. Interestingly, both the actions still use the continuous tenses. However, one action is in Future Continuous and the other – in Present Continuous.
We will enjoy the true equality when conjunction “and” is used in the meaning of “while,” in this case it serves as an entry to a point in time.
They will be playing online games, and we will be studying tenses. (and it will be 2 pm)
In this situation, both the clauses (sentences) are in Future Continuous.
This is one of the most difficult topics in studying English tense system. It requires a lot of practice until you do understand it.
Also on Future Continuous: