In some cases, the occurrence of one core FE requires that another core FE occur as well. To illustrate, in the Attaching frame Item, Goal, and Items all are core FEs. If Item occurs, then Goal is required, as shown below, where the sentence without a Goal is unacceptable. In this situation, we mark a Requires relation between the two frame elements. (19) The robbers tied [Paul Item] [to his chair Goal]. (20) * The robbers tied [Paul Item]. The Requires relation occurs in almost all frames that have a construal alternation between a symmetric construal, when a single frame element name is used, and an asymmetric construal, when two frame elements with names of the are used. In the former case a simple name of the form [FENAME]s is used and in the latter, two FEs of the form [FENAME]_1 and [FENAME]_2 are used. Some sample frames are Compatibility, Chatting, and Similarity; there are many more. xsd:string