一个物体以初速度1m/s做匀加速直线运动,经过一段时间后速度增大为7m/s,则( )
A:该加速过程中物体平均速度为5m/s
B:物体在该运动过程位移中点瞬时速度为4m/s
C:将该过程分为两段相等时间,则物体先后两段相等时间内的位移之比是5:11
D:将该过程分为两段相等位移,则物体先后两段位移所用时间之比是1:( 2 ﹣1)
根据下列自养生物合成有机物的反应式,推测三类生物在进化中出现的先后顺序是Ⅰ.蓝藻(需氧型)H2O+CO2 (CH2O)+O2Ⅱ.绿硫细菌(厌氧型)2H2S+CO2 (CH2O)+2S+H2OⅢ.硝化细菌(需氧型)2H2O+CO2 (CH2O)+O2+H2O
用所给词的适当形式填空 :(1)Who can jump the ____ (far) in your class, Sandy, Lucy or Kate?(2)Chen Kaige is one of the famous ____ (direct) in China.(3)The boy's ____ (die) is a great disaster to his parents.(4)There's always a risk of getting killed, so the family has to move away to another city for ____ (safe).(5)Shortly after, the ____ (France) director told me that he had devoted his lifetime to the industry.(6)Chinese people have found out the____ (true) through many years' struggle.
依次填入下列各句横线处的成语,最恰当的一组是( )
①医疗质量是关系到病人生命安危的大事,救死扶伤是医务人员 的天职。
②中国传统的严父慈母型的家庭关系,常令父亲们 地承担起教育子女的义务。
③在全国比赛中屡获金奖的我省杂技团, 地承担了这次出国演出任务。
人体内多种激素之间表现为协同作用.下列是某同学所作的归纳,其中有误的是( )