调查人员在开展火灾调查前，应当根据火灾现场情况，做好哪些工作？
["\u7b54\uff1a\uff081\uff09\u6392\u9664\u73b0\u573a\u9669\u60c5\uff1b\uff082\uff09\u5212\u5b9a\u73b0\u573a\u5c01\u95ed\u8303\u56f4\uff1b\uff083\uff09\u8bbe\u7f6e\u8b66\u6212\u6807\u5fd7\uff1b\uff084\uff09\u63a7\u5236\u706b\u707e\u8087\u4e8b\u5acc\u7591\u4eba\u3002"]