1. According to the company's qualifications, institutions with official certification from relevant government agencies will be at least much safer. 2. Look at the size of the company. Of course, looking at the size does not mean that looking at the information sent by the other party can prove how powerful your company is. The most direct and simple method is offline access. 3. Audition training class. If possible, try to arrange an audition class, offline is preferred, and online is also acceptable.