The future progressive tense refers to an action that will be underway at a particular time in the future. When used in conjunction with when + a present tense, the future progressive action will precede the present tense in time and may continue after it:

–The clerk will be weighing the bananas when you return.

TENSE FORMATION (Future Progressive)

Simply put the helping verb (a form of to be) into the future tense and use the -ing form of the main verb:

–We buy groceries.
–>We will be buying groceries.

Examples of Future Progressive

• Hi, will you be having lunch?