read the three paragraphs below and choose the sentence that is the main idea of the paragraph. _______1. (1) Often when older children move back home, unpleasant tensions and disagreements arise. (2) However, adult children who move back home can avoid family conflicts by following some tips. (3)First, they should contribute what they can and it need not be in terms of money: Being productive family members will help them earn their keep. (4)This can involve tutoring or coaching younger sisters or brothers, or helping Mom and Dad with chores and errands. (5)Second, these "resumes’ should not expect their parents to rescue them from difficulties. (6)As adults, they are responsible for getting out of their own scrapes -and for trying to avoid them in the first place. (7)Last, they must respect their parents' lifestyles and own needs for independence. (8)It is unrealistic to expect parents' lives to revolve around the needs of a grown child, in the manner they may have when the child was younger. ______2. (1) Scientists have learned that the way we view exercise strongly influences our performance. (2)Research on Russian weight lifters, for example, demonstrated that if they were told the weights were heavy, they perceived an exercise to be moreifficult. (3)1f they were told the weights were light, then they considered the exercise easier. (4) Another example is the weight lifter who kept failing to break a record. (5)He finally succeeded after his trainer told him the weights he was lifting were not as heavy as they in fact were. _____3. (1) Until the 1940s, most Americans were born and died at home. (2)Births and deaths happened when they happened, often without medical intervention. (3) If a baby was too premature or defective o if a seriously ill person was dying, there was little family doctor could do about it other than to offer comfort. (4)Today, most Americans are born and die in hospitals under the supervision of medical personnel who sometimes decide to keep them alive long beyond the point at which they would normally have died. (5) Patients can be hooked up for days, months, or years to machines that sustain their lives. (6) This step may be taken even if e inconstant pain or permanently comatose. (7) Obviously, technology has greatly changed how we are born and die.