"A esa hora ya habré llegado" "Debería haber terminado para octubre" "Él dijo que estría aquí a esta hora" This is a little bit hard to explain for me, but I'll try. "By" could most of the times be translated to spanish as "por", but when translating every sentence where it is used, "por" will not be an adequate preposition for using nor a good translation; sometimes there is not even a preposition involved. Let me explain: In the case of "You can achieve anything by studying hard", it would be translated as "Puedes alcanzar cualquier cosa estudiando duro". Any preposition was used there. Let another case be "You need to get here by car", it would be translated as "Necesitas venir en carro". The preposition "en" was used instead of "por". The obvious case is when the translation is "por". So, you don't always have the same translation of "by", sometimes you don't even use it. So, in order to translate it correctly, you need to think about which preposition could be used. Most of the times in spanish, and even in english, when talking about time it is understood (it seems, I've never thought about this before) that you are inside a frame of time. So you are "en una hora", "en octubre", "en un rato". However, when you say "now" you can use "ahora", or in this case "a esta hora", because you can be precise about the time. "a" is a very versatile preposition. You can use "a" when you state some definite time "a esta hora", " a las 10:00". Also, you can use it when stating a distance in amounts of time "está a una hora de aquí". However, when talking about a frame of time, you use "en" as stating that something will happen in that interval of time, or past that time: "en una hora llegaremos", "en la mañana". Yet another disclaimer: if you say "en la mañana siguiente" (being in that frame of time) you can also say "a la mañana siguiente" (as moving the time forward, "a" as "hacia"). I always recomend http://dle.rae.es/ as a dictionary. Hope this can help you :).

A good page for information regarding words, and other things too, you can always search in the dictionary of the Royal Spanish Academy: http://dle.rae.es/ 1. Asistencia: is to be present, or to be present in an act. The meaning that this word have for help (ayuda) comes from the act of asking assistance as if you ask for someone to get involven in an act that concerns you. Ayuda: to cooperate with someone in order to achieve something. Auxilio: synonim of 'ayuda', can mean 'substitute', 'medical help' in the case of the noun 'auxiliar'. It, as well as 'ayuda', doesn't have the meaning of help because of a way of using that word with another meaning, like 'asistencia', but was "created" with that meaning. Socorro: is a help that is given in a state of danger. 2. Preparar: is to create something, or organize it in order to do something. So, when you are 'prepared', means that everything has been arranged for accomplishing a goal, as to withstand a situation. Capacitar: 'capaz', being able to do something, that's where the verb comes from. It is the act of making someone, has to be a person, able of doing something, making them capable. You can't capacitate a sandwich but you sure can prepare it. :D 3. Consejo: an opinion that is given as help. This is funny, because 'consejo' also means the group of people that assisted (asistencia) the king in his decisions. They take parts in an act that the King is involved in, and give him assistance. Asesoramiento: comes from the act of 'asesorar', which is giving an advice (consejo) or an order. So 'asesoramiento' is the act and the result of 'asesorar'. Wether it is the act or the result is to be determined according to the context where the word is used. 4. Subsidio: an economic contribution. It can be seen as an economic help. Subvención: Also, an economic contribution. It can also mean to go to help someone or to aid him in his necessities, not necesarily economic.