If the ovulation test paper shows a strong positive, and then weak, showing that there may be ovulation within 24-48 hours, and then a strong positive after the next day, there are two kinds of reasons: 1, the ovulation test paper may have an error, not as accurate as the ultrasound display, it is possible that the follicle has already been discharged. 2, it may be that the follicle has not been discharged, and the formation of luteinized cysts is considered, and it may be that the next day after the strong positive again. If you are preparing for pregnancy, the most intuitive and accurate is ovulation, you need to go to the hospital in time to do ultrasound to monitor ovulation, is the gold standard for monitoring ovulation. If the ultrasound shows that there is a follicle of more than 1.8 centimeters, it is considered to be a mature dominant follicle, which may be ovulated in 24-48 hours, and it is recommended to have intercourse once every other day, and then review the ultrasound after 3 days, the chances of conception are relatively high.