Understanding the difference between in and within
In and within may appear similar but their use in English grammar is quite different. In is a preposition which describes a noun’s location. In describes a specific object or person in a certain area or place . For instance in the following sentence in describes the location of the object –ball . The ball is in the store, in this case the store being the place being described by the preposition in .
Within clearly brings out the sense of right inside. For example , I will do all that is within my capability .In the above sentence within brings about the idea of whatever which is under the umbrella of his capability .
When used with other words the words in and within can bring out different meanings , like in the following case . He arrived on time, this means that he was not late .In another sentence like the following the meaning changes completely. i.e He arrived within two hours , this implies that he arrived sometimes less than two hours after a specific time .
Thus according to the argument above it is of interest to note that in is used to mean less than or below while within is used to imply before .
Taking a look at the sentence ; He came in two hours you get an impression that he came at the end of two hours hence the preposition in is used to mean that as the two hours were ending he showed up . These two words are also combined with other verbs.