Future tense 2 – Future perfect Continuous

1. Introduction

The future perfect continuous tense describes a continued action at some point in the future, is composed of two elements :
the future perfect of the verb “to be” (will have been) + the present participle of the main verb (base + ing)

2. Explanation

The future perfect:

• has the form will + have + been + verb-ing.
  For example: He will have been travelling for six months by the time he goes to Spain.
• describes continued actions that are continuing at a specific point in the future.
  For example: We should hurry because Barbara will have been waiting for us for ten minutes already.
• uses “not” in negative form.
  For example: We’re early, so Barbara will not have been waiting for us yet.