A:电磁波可能是横波, 也可能是纵波, 而且能发生干涉、衍射现象
B:由麦克斯韦电磁理论可知,振荡电场一定要产生同频率振荡磁场
C:电视机天线接收到高频信号后,依次经过解调、调谐, 再将图像信号送到显像管
D:雷达利用无线电波的短波波段来测定物体位置的,它利用了短波的衍射性质
学校开展阳光体育活动,有利于增强学生体质,提高抵抗力,预防传染病,该措施属于( )
根据短文内容,判断正(T)误(F)。 My name is Bill. I get up at twenty to seven in the morning. Then I have breakfast. After breakfast I go to school. We have four classes in the morning. I have lunch at school, but on Sundays I have lunch at home with my family. I often have supper at home. I often help my mother cook. My mother is an English teacher, and she often helps me with my English.
右图为光照强度对植物光合作用强度的影响关系。下列有关曲线的叙述中错误的是