题目

A healthy lifestyle is related to physical and mental fitness．Therefore, it’s time for you to make some changes to lead a healthier life and put yourself ___41___ ease. Nowadays many people say they just don't get much time to look after    42  （they） health．Actually，it is ___43___ you do and eat every day that guarantees you a healthy body．So make some little changes in your schedule to improve your lifestyle．It's never too late． These are some suggestions 44 （give） by health experts which can help you achieve your goal．First of all，add healthy food to your维生素A1中含C的质量分数为83.9%，H为10.5%，O为5.6%，其相对分子质量是286，则维生素A1化学式为（ ）A．C19H28O2B．C20H14O2C．C20H30OD．C19H42O