64. stretch out: 伸直 On warm days, bears stretch out or lie on their backs with their feet in the air. 天气暖和的时候，熊会平躺下来，或四脚朝天仰卧着。
65. at the most: 最多，至多=at most/at the utmost at best: 顶多，充其量（贬义） Cherry blossoms last only for a few days, a week at the most. 樱花花期只持续几天，不超过一个星期。
66. get/be/stay/keep in touch with: 与……联系 反义：lose touch with; out of touch with If I knew his address, I would get in touch with him right away. 如果我知道他的地址，我会马上和他联系。
67. act on: 影响，作用于；奉行，遵照……行动（=act upon） Does the medicine act on the stomach? 这药对胃起作用吗？ work v.起效 a sleeping pill works for 8 hours 安眠药药效8个小时。
