It may be different from your school system. Take Wanfang and HowNet as examples. If the school and Wanfang are unified, you can use HowNet to query, and the repetition rate will be different. On the contrary, if the school is HowNet, you use Wanfang. It's also different. Another reason is that the content you copied is not in these two websites or the website you checked again, so the display will be very low.