i Register
In some senses, difficult is marked as obsolete. Watch for register when choosing this word.
VERBS
be, look, prove, seem, sound
become, get
As the project continued, the instructions became increasingly difficult to follow.
make sth
The bad weather made it difficult for us to finish the outdoor work on time.
find sth
ADV
exceedingly, extraordinarily, extremely, incredibly, particularly, really, very
doubly
Learning a new language while working full-time is doubly difficult for most adult students.
increasingly | a bit, quite, rather
notoriously
Teenage years are notoriously difficult for both parents and children.