KEY: Future Perfect Tense is used to express an activity that will be completed before another time or event in the future. In other words, This tense indicates the completion of an activity by a certain future time. To express an event or an activity, there must be a preword before the tense is stated.
Study this follows!
1) I will take an English course in February.
2) I will work for Microsoft,inc in August.
By the next time I work for Microsoft,inc., I will have taken an English Course.
The first activity is /I will have taken an English Course./ and second one follows; /I work for Microsoft,inc.,/.
Take notice that both activities happen in the future time. Let me say that this tense is combination between Simple Future Tense and Present Perfect Tense. Note : /By the next time/ introduces a time clause.
Study this following structure!
(+) Subject + Will/shall + Have + Past participle
(-) Subject + will/shall + not + have + Past participle
(?) Will/shall + Subject + Have + Past participle (?)
(+) She will have finished my assignments by that time.
(-) She won't have finished my assignments by that time.
(?) Will she have finished my assignments by that time ?
Note: /won't/=/will not/.