The future perfect passive is formed with the structure: WILL HAVE BEEN + PASSIVE PARTICIPLE
Here’s an EXPERT EXAMPLE of future perfect passive:
If you live to 90, then 32 years will have been spent entirely asleep.
The ending -t in (spent) is an irregular inflection for the passive participle, which regularly ends in -ed:
PEARSON GSE 67 B2+ future perfect passive simple is oddly unlisted in the English Grammar Profile. The EGP does have perfect passive at B2, but no mention of it with ‘will have been + past participle’. For that reason here we will include a point that deserves at least B2 mention.
A search in iWeb for:
will have been _VVN
1 WILL HAVE BEEN MADE 366
2 WILL HAVE BEEN GIVEN 252
3 WILL HAVE BEEN SENT 235
4 WILL HAVE BEEN CREATED 228
5 WILL HAVE BEEN REMOVED 217
6 WILL HAVE BEEN TAKEN 195
7 WILL HAVE BEEN COMPLETED 183
8 WILL HAVE BEEN USED 177
9 WILL HAVE BEEN LOST 165
10 WILL HAVE BEEN REPLACED 149
11 WILL HAVE BEEN EXPOSED 122
12 WILL HAVE BEEN SET 121
13 WILL HAVE BEEN PROVIDED 120
14 WILL HAVE BEEN WASTED 119
15 WILL HAVE BEEN PAID 117
16 WILL HAVE BEEN ADDED 109
17 WILL HAVE BEEN SPENT 105
18 WILL HAVE BEEN BUILT 99
19 WILL HAVE BEEN RELEASED 98
20 WILL HAVE BEEN SAVED 96
21 WILL HAVE BEEN ACHIEVED 91
22 WILL HAVE BEEN REDUCED 88
23 WILL HAVE BEEN TRAINED 83
24 WILL HAVE BEEN DESIGNED 79
25 WILL HAVE BEEN LEFT 79
26 WILL HAVE BEEN PUT 79
27 WILL HAVE BEEN WRITTEN 79
28 WILL HAVE BEEN SEEN 76
29 WILL HAVE BEEN ISSUED 71
30 WILL HAVE BEEN RAISED 71
31 WILL HAVE BEEN TREATED 71
32 WILL HAVE BEEN AFFECTED 70
33 WILL HAVE BEEN BORN 67
34 WILL HAVE BEEN INSTALLED 67
35 WILL HAVE BEEN TESTED 66
36 WILL HAVE BEEN PLAYED 65
37 WILL HAVE BEEN ASKED 64
38 WILL HAVE BEEN INTRODUCED 64
39 WILL HAVE BEEN PRODUCED 63
40 WILL HAVE BEEN ESTABLISHED 62
41 WILL HAVE BEEN SOLD 60
42 WILL HAVE BEEN DESTROYED 59
43 WILL HAVE BEEN TOLD 59
44 WILL HAVE BEEN UPDATED 58
45 WILL HAVE BEEN DEVELOPED 56
46 WILL HAVE BEEN FOUND 56
47 WILL HAVE BEEN CHANGED 55
48 WILL HAVE BEEN KILLED 55
49 WILL HAVE BEEN BROUGHT 54
50 WILL HAVE BEEN SELECTED 54
51 WILL HAVE BEEN TRANSFORMED 53
52 WILL HAVE BEEN ABSORBED 52
53 WILL HAVE BEEN ACCOMPLISHED 52
54 WILL HAVE BEEN REACHED 52
55 WILL HAVE BEEN TAUGHT 52
56 WILL HAVE BEEN CONVERTED 51
57 WILL HAVE BEEN COVERED 50
58 WILL HAVE BEEN CUT 49
59 WILL HAVE BEEN FULFILLED 49
60 WILL HAVE BEEN PREPARED 49
61 WILL HAVE BEEN GAINED 47
62 WILL HAVE BEEN DETERMINED 46
63 WILL HAVE BEEN PASSED 46
64 WILL HAVE BEEN LEARNED 44
65 WILL HAVE BEEN IDENTIFIED 43
66 WILL HAVE BEEN DEEMED 42
67 WILL HAVE BEEN ELIMINATED 42
68 WILL HAVE BEEN GENERATED 42
69 WILL HAVE BEEN BROKEN 41
70 WILL HAVE BEEN ASSESSED 41
71 WILL HAVE BEEN EMAILED 41
72 WILL HAVE BEEN ASSIGNED 40
73 WILL HAVE BEEN FORGOTTEN 40
74 WILL HAVE BEEN MET 40
75 WILL HAVE BEEN PLACED 39
76 WILL HAVE BEEN TURNED 39
77 WILL HAVE BEEN CARRIED 38
78 WILL HAVE BEEN APPLIED 38
79 WILL HAVE BEEN DELETED 38
80 WILL HAVE BEEN MOVED 38
81 WILL HAVE BEEN OFFERED 38
82 WILL HAVE BEEN DIAGNOSED 37
83 WILL HAVE BEEN DISAPPOINTED 37
84 WILL HAVE BEEN DECIDED 37
85 WILL HAVE BEEN ADVISED 37
86 WILL HAVE BEEN RECORDED 37
87 WILL HAVE BEEN ALLOCATED 36
88 WILL HAVE BEEN FORCED 36
89 WILL HAVE BEEN TRANSFERRED 36
90 WILL HAVE BEEN FORMED 35
91 WILL HAVE BEEN OBTAINED 35
92 WILL HAVE BEEN RESOLVED 34
93 WILL HAVE BEEN SHOWN 34
94 WILL HAVE BEEN CHECKED 33
95 WILL HAVE BEEN COLLECTED 33
96 WILL HAVE BEEN INCLUDED 33
97 WILL HAVE BEEN LAID 33
98 WILL HAVE BEEN CONSIDERED 32
99 WILL HAVE BEEN ENCOURAGED 32
100 WILL HAVE BEEN RESTORED 32
B2 verbs:
absorbed, affected, assessed, converted, determined, established, exposed,
forced, generated, identified, obtained, placed, released, restored, transformed, treated