Three situations, one is the protective response of leaves caused by exposure, which only needs shading. Second, too much watering, or long-term wet soil, leads to excessive expansion of roots and leaves, leading to bending on both sides of leaves. In this case, you need to stop watering immediately, take off the pot and dry the roots carefully, and then water them again when the leaves wilt a little. Third, there are many kinds of diseases and insect pests, including red spiders and aphids, so I won't list them one by one. Insects can be killed with pesticides, but diseases are generally incurable (there is a way), and the growth of plants will get worse and worse, and it will be contagious. It is recommended to deal with it immediately.