1, apply for trial, and search for information;
2. Search for some projects that you have cooperated with before to see if the content of the report and related companies and contacts are consistent with the information you know;
3. Search for some items you are interested in and try to make a few phone calls to verify the accuracy of the information inside;
4. Go to the office of the information company to see the geographical location and personnel size;
5. Ask friends who work in large building materials enterprises and listen to their opinions.