Routines: personal 'a' and contraction 'al'

In Spanish we use a personal 'a' between the verb and the direct object if the object is a specific person or pet. The article 'el' ('the') refers to a singular masculine noun. If personal 'a' is followed by 'el', it becomes 'al'. Some adjectives come before the noun in Spanish, these are called prenominal adjectives, e.g. 'mismo', 'propio'. Certain prenominal adjectives, 'bueno', 'primero', 'tercero' and 'malo', lose their -o ending before a masculine noun. These adjectives may appear in sentences with personal 'a' or 'al', e.g. 'conoces a un buen doctor'.