Las preguntas del examen fueron difíciles, pero logré responder varias.
The exam questions were difficult, but I managed to answer several.
Context: school Esos retos son difíciles, pero valen la pena enfrentarlos.
Those challenges are difficult, but they are worth facing.
Context: personal growth Algunos temas de historia son difíciles de entender.
Some history topics are difficult to understand.
Context: education