1 With so many young, single people having babies, the question arises as to how happy they are being young parents. 2 A national survey of young, single mothers and fathers reveals that most were happier before they became parents. 3 Sixty-seven percent of the nine thousand new parents who responded to the survey said having a baby presented more problems than they envisioned. 4 Fifty-six percent of the respondents said they had to drop out of school, despite their hopes that they could manage schoolwork plus rearing a baby. 5 A majority (73 percent) said they were forced to seek financial help from family, friends and/or government agencies, and 37 percent said they accepted low-paying, unsatisfying jobs out of necessity. 6 Also, 70 percent said they missed the “good times” with friends that they enjoyed before their babies were born. The main idea is sentence____. ( 请写出句子的序号,例如: 1)