Resolving ambiguity in merged English verb forms

In English writing, it is customary to merge the pronoun subject and the following auxiliary verb as a single string, pointing the abbreviated part with an apostrophe. Part of these structures can be spelled out unambiguously. However, there are structures, where the verb can be either be or have. In other structures, the verb can be will, shall, would, could, or have. The problem can be solved only on the basis of context. There are also genitive structures, which look very much the same as the verb structures. These must be kept separate and treated accordingly. The report discusses these problems.