Answer:
A mi amigo LE gusta vivir en las afueras de la ciudad.
Explanation:
The verb <em>gustar</em> (to like) has a different conjugation form than the regular ones. The verb combines with the object (a thing or a person we like) and not we the subject.
A mí me GUSTA Ana.
<em>Gusta </em>is singular because the object is ONE.
A mí me GUSTAN Ana y Pablo.
<em>Gustan </em>is plural because the object is MULTIPLE.
Besides that, we always have to use the indirect object form for the subject.
a mí ME a nosotros NOS
a tí TE a vosotros OS + gusta/ gustan
a él LE a ellos LES
In this example, the missing word is LE because <em>mi amigo </em>is ÉL (he). And the verb is <em>gusta </em>(singular) because <em>vivir en las afueras de la ciudad</em> is singular.
