Breakdown of Es injusto que el profesor te castigue por eso.
ser
to be
eso
that
el profesor
the teacher
que
that (relative pronoun, conjunction)
Questions & Answers about Es injusto que el profesor te castigue por eso.
Why is there a "u" in castigue?
Castigue comes from the verb castigar (to punish). In the present subjunctive, the endings for -ar verbs start with "e". If we just swapped the "a" for an "e" to make castige, the "g" would sound like an English "h" (as in gente). To keep the hard "g" sound of castigar, Spanish spelling rules require changing the "g" to "gu" before an "e".
Why do we need the subjunctive castigue here?
The phrase starts with es injusto que (it is unfair that). This is an impersonal expression that shows a subjective opinion or judgment. In Spanish, expressing an opinion or emotion about what someone else does almost always triggers the subjunctive in the following clause.
Why do we use por instead of para in por eso?
Why is it eso and not ese or esa?