assign
as + sign
egg
As a content word it needs three letters.
a__opt
<ad>
adopt
co__nect
<con>
connect
prefix
<pre> means 'before'
oppose
op + pose
pass
Plural cancelation, 'floss' rule.
a__sort
<as>
assort
co__pare
<com>
compare
submarine
<sub> means 'under'
support
sup + port
off
'floss' rule, content spelling, different from <of>
a__tach
<at>
attach
co__bine
<com>
combine
incapable
<in-> means 'not'
comparable
com + pare + able
(the <e> is replaced in this word but is there in the base element)
reddest
Double the consonant when adding a vowel suffix (the doubling rule).
a__cept
<ac>
accept
co__rupt
<cor>
corrupt
obstacle, obstruction
<ob-> means 'in the way of, facing'
occurring
oc + cur + ing
(the <r> doubles in this word but is single in the base)
attract
<at> is an assimilated prefix
a__gravate
aggravate
co__lege
college
inspire, inject
<in-> means 'in, into'