A、Provide professional standard care. B、Be affectionate and cooperative. C、Be frank and seek help from others. D、Make full use o

　　When people care for an elderly relative, they often do not use available community services such as adult day-care centers. (19) If the caregivers are adult children, they are more likely to use such services, especially because they often have jobs and other responsibilities. In contrast, a spouse, usually the wife, is much less likely to use support services or to put the dependent person in a nursing home. (20) Social workers discover that the wife normally tries to take care of her husband herself for as long as she can in order not to use up their life savings. Researchers have found that caring for the elderly can be a very positive experience. The elderly appreciated the care and attention they received. They were affectionate and cooperative. However, even when caregiving is satisfying, it is hard work. Social workers and experts on aging offer caregivers and potential caregivers help when arranging for the care of an elderly relative. One consideration is to ask parents what they want before they become sick or dependent. Perhaps they prefer going into a nursing home and can select one in advance. On the other hand, they may want to live with their adult children. (21) Caregivers must also learn to state their needs and opinions clearly and ask for help from others, especially brothers and sisters. Brothers and sisters are often willing to help, but they may not know what to do.
　　19.  Why are adult children more likely to use community services to help care for elderly parents?
　　20.  Why are most wives unwilling to put their dependent husbands into nursing homes?
　　21.  According to the passage, what must caregivers learn to do?