My father is very busy and doesn't come back home until midnight.
生物体细胞的体积趋向于小的原因是（ ）
小华给客人沏茶，接水1分钟，烧水7分钟，洗茶杯2分钟，拿茶叶1分钟，沏茶1分钟，小华合理安排以上事情，最少要（ ）分钟使客人尽快喝茶．
