Verbs not used in progressive forms
Some verbs are never used in progressive forms. Examples are: like, need,
believe, doubt, feel, imagine, know, love, hate, prefer, realize, recognize,
remember, see, suppose, think, understand, want, wish etc.
I like this kind of music. (NOT I am liking this kind of music.)
I need to talk to him. (NOT I am needing to talk to him.)
Most non-progressive verbs refer to states rather than actions. There are also some verbs which cannot be used in the progressive form with certain meanings. Examples are: feel, see, think and measure.
When the verbs think and feel mean ‘have an opinion’, they cannot be used in the progressive.
I am feeling fine. (= I feel fine.)
I feel that (= have an opinion) he is wrong. (NOT I am feeling that he is wrong.)
I think (= have an opinion) you are correct. (NOT I am thinking you are correct.)
When see means ‘understand’, it cannot be used in the progressive.
I see what you mean. (NOT I am seeing what you mean.)
Can with non-progressive verbs
Can is often used with non-progressive verbs like see, hear, feel, taste, smell and understand to give a kind of progressive meaning. This is common in British English.
I can smell something burning.
Even verbs which are never used in progressive tenses have -ing forms that can be used in other kinds of structures.