The correct answer is: "Es preciso que uses sombrero"
In english (if needed): Pamela: "How can I protect my face from sunburn?" Roberto: "It's necessary to wear a hat."
Hoped I helped ^.^
Ser and estar both mean “to be”. Ser is used to talk about WHAT something is. This includes date, occupation, characteristics, time, origin, and relationship. Estar is used to talk about HOW something is. This includes position, location, action, condition, and emotion.
Examples of ser:
-Yo soy alta.
-Ella es inteligente.
Examples of estar:
-El está triste.
-Estoy mirando la tele.
Desde hace makes the most sense. The best form for this sentence is, "Te espere` una hora." It's shorter and direct.
