The irregular verb "mögen" is the only one of the modal verbs which does not have to be followed by an infinitive. When it takes a direct object, it simply means to like something. The usage of "gern" is optional:
Magst du die Brosche? Ja, ich mag sie.
(Do you like the brooch? Yes, I like it.)
Mögt ihr Abenteuerfilme? Nein, wir mögen sie nicht.
(Do you like adventure films? No, we don't like them.)
Mag er Popmusik? Ja, er mag Popmusik gern.
(Does he like pop music? Yes, he likes pop music.)The verb "gefallen"
The second verb which can used to express likes and dislikes is the irregular verb "gefallen", which means "to please":The verb takes the dative case, such that "das gefällt mir" means "that pleases me". But it is equally used to translate "I like it", wherby the English speaker must remember that it in the German construction, it is the thing which is being liked which is the subject of the sentence. The person doing the liking is in the dative case. The addition of "gut" for emphasis is an optional extra. For example:
Gefällt dir die Brosche? Ja, sie gefällt mir.
(Do you like the brooch? Yes, I like it.)
Gefallen euch Abenteuerfilme? Nein, sie gefallen uns nicht.
(Do you like adventure films? No, we don't like them.)
Gefällt ihr das Schloss? Ja, es gefällt mir ganz gut.
(Does she like the stately home? Yes, see likes it.)
Gerne
You would use "mögen" and "gefallen" to describe whether you like objects or not. To explain what you like doing, simply add the adverb "gern(e)" after the verb denoting the action in question. If you don't like doing an action, add nicht gern(e):
Grammar 12: Gern(e)
Händel höre ich gern.
("I like listening to Händel.")
Händel höre ich nicht gern.
("I don't like listening to Händel.")
Was essen Sie gern?
("What do you like to eat?")
Ich esse gern Pommes frites.
("I like eating chips.")