Silent letters

This is a post about letters, particularly consonantal ones, which are not pronounced. The most common cases have been omitted, e.g. the "-e" in take.

Ex. In each set choose the word which is pronounced differently from the remaining words. Indicate which letter is or is not silent.

a. past - bath - party - logically
b. dumb - plumber - number - tomb
c. school - cause - muscle - cane
d. obtain - doubt - debt - bomb
e. castle - thistle - jostle - mostly
f. thyme - thick - thin - three
g. signing - reign - benign - ginger
h. hotel - honour - horror - hostel
i. heir - hair - hourly - honestly
j. folk - yolk - bulk - stalk
k. Malmö - palm - calmer - embalm
l. knowledge - acknowledge - knead - kneel
m. hymn - condemn - damnation - damn
n. pterodactyl - psalm - upside - psychology
o. corps - corpse - corporal - copious
p. choir - chorus - technical - church
q. gullet - ballet - bouquet - valet
r. fax - faux - lax - box
s. singsong - parson - lesson - person
t. wrapper - lower - whistle - white
u. wear - weary - more - merely
v. amazing - zany - lazy - rendezvous

KEY
a. logically silent "a",
b. number non-silent "b" (but number, the comparative of numb, also has a silent "b") ,
c. muscle silent "c" ("sc" pronounced /s/)
d. obtain non-silent "b"
e. mostly non-silent "t"
f. thyme silent "h" ("th" pronounced /t/)
g. ginger non-silent second "g"
h. honour silent "h"
i. hair non-silent "h" (in RP)
j. bulk non-silent "l"
k. Malmö non-silent "l"

l. knowledge non-silent "n"

m. damnation non-silent "n"

n. upside non-silent "p"

o. corps silent "p" (actually the entire word is pronounced just /kɔː/)

p. church both "h"s in "ch" are pronounced

q. gullet non-silent "t"

r. faux "x" is silent

s. singsong non-silent "o" (no syllabic /n/)

t. wrapper silent "w"

u. weary non-silent "r" (in RP)

v. rendezvous silent "z"