Question

Choose the option that fills in the blank with the most appropriate verb form:
He __________ by the time you telephone his house.

• A. had left
• B. will have left
• C. has left
• D. was leaving

Answer 1

The correct option is B will have left

Here, 'will have left' in Future Perfect Tense is correct because it is used to indicate an action that will be complete before another event takes place. Here, 'by the time..' indicates an action that will be complete before another event takes place.
'Had left' in past perfect is incorrect because it is used to indicate a completed action of the past that happened before another event took place.
'Was leaving' in past continuous is incorrect because it is used to indicate uncompleted action in the past (with or without time reference).