It is reasonable to say that there should be no charge, because the school will buy the digital resources of HowNet, so it is normal to download them for free. The reason for the charge may be that you often operate. It is recommended to rest for 3~5 minutes before operation. If it doesn't work, log in again. If there is any news of charging tips, it is not excluded that the resources of HowNet purchased by your school are inexhaustible. It should be said that this phenomenon is normal. For example, if your school is an engineering college, the more resources about engineering, the better. However, some resources about social science may be purchased, which is also related to the purchase of corresponding digital resources by schools. If this phenomenon still can't be handled, I suggest you go to Taobao and spend about 5 yuan to buy an account with a mirror image of HowNet, which can be used for 3 months. It is very convenient and you don't have to worry about downloading papers. Good luck ~