【单选题】The scientists are not sure______.
A.
how long the ice age lasted
B.
where ice sheets melted during the ice age
C.
what caused the temperature changes
D.
what the earth is made up of
【单选题】The scientists are studying the effects of human activities______the environment.
【判断题】蓝牙和移动ad hoc网络在通信基础架构方面与无线传感器网络完全不同。
【单选题】The world's population is getting larger and larger, so the scientists are trying to new ways to solve the food problem. [ ]
【单选题】The scientists are able to ____________ accurately when the spaceship will reach the moon.
【判断题】蓝牙和移动ad hoc网络在通信基础架构方面与无线传感器网络完全不同。
【单选题】关于对称与均衡的描述错误的是 。
A.
对称是以一条线为中轴,形成左右、前后或上下在量上的均等
B.
均衡是对称的一种延伸,是事物的两个部分在量上大致相当
【单选题】对脑和长骨的发育最为重要的激素是( )。