Some damage has been caused u____ by people simply walking around the site and some has been caused deliberately.
身高突增是青春期的一个显著的特点,其中女孩子的发育早于男孩.(判断对错)
已知抛物线y=ax2+bx+c经过A(﹣1,0)、B(3,0)、C(0,3)三点,直线l是抛物线的对称轴.
我国最早种植水稻的原始居民是( )