6 Finding verbs in a dictionary
When you want to look up a verb in the dictionary, you will generally find only the infinitive form. So, if you are reading a text and come across a verb you don’t know, such as corremos, you first need to detach the ending (in this case -emos) to get the stem (in this case corr-) from which you get the infinitive correr (‘to run’); you know it’s an -er verb because of the e in -emos. Now you can look up the verb correr in the dictionary.
If the verb form you are looking up happens to be irregular, this procedure for finding the stem may not work. For example, if you have the verb form es, you need to know that es is the third person singular of ser.