Hola Gail, thanks for your question and sorry about our delay. We need to add that exceptional case to our lesson. The rule says that when using a command in the "vosotros" form ending by -d with pronouns starting by a vowel, we need to remove this -d from the imperative form. This is done mainly due to phonetical reasons, because it is easier and more confortable to pronounce two vowels together in this case. Thanks again for contacting us and we will fix this in the lesson as soon as we can. Silvia