This document summarizes a survey of 62 semantic question answering systems published between 2010-2015. It identifies 7 key challenges for SQA systems: lexical gap, ambiguity, multilingualism, complex queries, distributed knowledge, procedural/temporal/spatial questions, and templates. For each challenge, it describes common solutions and how Adam QA addresses each challenge, which is mostly partially or not at all currently. The conclusion recommends modularity, reuse of components, and benchmarking of individual algorithmic modules.