题目

Although she is a ______ girl, she know a lot of Chinese characters(汉字)      A. five years old    B. five- year-old    C. five-years-old      D. five-year-olds 答案：B振荡试管内的液体时，正确的操作是（ ）A．用手紧握试管，用臂晃动B．用手捏住试管，用腕摇动C．用手紧握试管，上下晃动D．用拇指堵住试管，上下晃动