说出五种以上常用实验动物每分钟呼吸频率。
参考答案:
羊:12~20,
猪:12~18,
狗:11~37,
兔:38~60,
大鼠:66~114,
小鼠:84~230。
Though some foreign scientists had a ________ opinion of his new invention, his fellow workers never
thought ________ of it.[ ]
A.highly;low
B.low;high
C.high;highly
D.poor;highly
量筒内盛有适量的水,将一个体积为8厘米3 的铁块跟一木块栓在一起,全部浸没在量筒内的水中,水面升高20厘米3,已知木块的质量为7.2克,则木块的密度为( )
A.0.36×103千克/米3
B.0.4×103千克/米3
C.0.6×103千克/米3
D.0.72×103千克/米3