Adjectives
harmless
past simple
This is done 100% of the time
Always
muhrlaf
harmful
easy to use
convenient
She was reading her book.
past continuous
This one happens less frequently than 'sometimes' but more than 0%
Seldom
Hardly ever
Rarely
Not often
hltwrewiho
worthwhile
that produces the desired results
effective
They have finished painting the room.
present perfect simple
This is not as often as 'always' but more than frequently.
Normally
iiinnprsg
inspiring
not very sensible or easy to use
impractical
The students have been studying for their tests.
present perfect continuous
This happens once every month.
Sometimes
Occasionally
lpatrciamic
impractical
worthwhile
The window has been being opened.
present perfect simple passive
This happens once in a blue moon.
Seldom
Hardly ever
Rarely
Not often
llaaeuvb
valuable