现代临床医学中，若要给患者做手术，一般会在手术前对患者实施局部或全身麻醉。世界上最早制成全身麻醉药剂的人是(      )

染色体组是指细胞中的一组____ 染色体，在形态和功能上各不相同，携带着控制生物生长发育的全部____．

①喝白开水 ②喝生水  ③睡懒觉  ④随地大便  ⑤不勤洗手 ⑥不勤潄口．

    William Henry Harrison, the ninth President of the USA, was born in a small town. When he was a boy, he was very quiet and shy. Because he was so quiet, everyone thought that he wasn't bright. People in the town often put a nickel(五分镍币)and a dime(十分硬币)before him and asked him which to choose. He always chose the nickel and they laughed.

    One day a woman felt sorry for him. She asked, "Why do you never take a dime and always choose a nickel? Do you know a nickel is worth(值……钱) much less than a dime?"

    "Certainly I know it.” William answered slowly. "But if I choose the dime, they will not ask me to choose them any more.”