Ordinary people should add an A to their movements, such as llevo el libro al medico, where medico is the receiver of movements and al is the abbreviation after masculine nouns. In another case, the verb prototype is added after al to indicate when. . . . When, such as Alf Pedro, estaba trabajando. Therefore, whether it is said in the past or in the future, the word "al" always follows the original verb. I don't know the rest, I can only answer you these.