Please stand with Ukraine in this difficult time. 

armchair, chair or sofa are comfortable

This armchair is quite comfortable. 

vs.

It is convenient that my job is close to my home. 

My job is conveniently located.

comfortable, vegetable, doable, remarkable, admirable, adorable, agreeable, available

able is a suffix meaning it is added to the end of the word - pronounication as if you were to say "a bull" when it is a part of a word

Explanation of prefix vs. suffix

happy - unhappy (un = prefix un= not so - not happy) 

happiness - ness - is a suffix which means state of being or the condition 

un = prefix

able vs. unable - I am able to swim.  I am unable to fly a plane. 

I am able to speak English. The pronunciaton is different 

able - /ˈeɪb(ə)l/ 

appear, hear, look, notice, recognise, resemble, see, seem, smell, sound, taste

adore, appeal, appreciate, desire,despise, detest, dislike, fear, feel, forgive, hate, like, love, mind, need, pity, prefer, satisfy, trust, want and wish

Be - stative and non-stative uses  

Conjugating of the verb be: I am, You are, He is, She is, It is, We are, You are, They are 

Exist - stative use only

mean, realise, suppose, suspect, think, understand

believe, consider, doubt, expect, imagine, know, realise 

Communication Stative Verbs: agree, deny, disagree

These 3 verbs must be used in the present simple not the continuous

Verb - describes an action

Stative verbs - describe states of being. ex. I am happy/angry/sad/mad.

Stative verbs - are used in the present simple tenses

When stative verbs don't describe a state but an action then they are used in the continuous tenses. 

ex. I have a cup of coffee in the morning.  (state)   vs.  I am having a cup of coffee now. (action)

     She has a cough. (state) vs. She is caughing. (action)