A:预备卫星的周期大于工作卫星的周期,速度大于工作卫星的速度,向心加速度大于工作卫星的向心加速度
B:工作卫星的周期小于同步卫星的周期,速度大于同步卫星的速度,向心加速度大于同步卫星的向心加速度
C:为了使该颗预备卫星进入工作卫星的轨道,应考虑启动火箭发动机向前喷气,通过反冲作用从较低轨道上使卫星加速
D:三个轨道平面只有一个过地心,另外两个轨道平面分别只在北半球和南半球
He was told ____ (drive) carefully.
Dear John,
How are you? Nice1 you. From your letter I know a lot about you and your school. Now let me2 something about me and my school.
I am thirteen years old. I am 3 Class Two, Grade One. My father is a teacher. He is my 4English teacher. My mother is a doctor. I have a sister.5 are in the same school. We can sing(唱) many songs6 English.
This is my classroom.7have a class photo on the wall. But can you see 8photo? It's at the door. In the classroom 9 our desks and chairs. Mrs. Green is our head teacher.10 is very kind(友好).
Please come and have a look at our school if you are free.
Millie
小刚在班里是个独来独往的人,他认为自己既没有做错事,也不有求于人,因此没必要去和别人交往。可是后来,他渐渐地觉得自己越来越孤独。看到同学在一块有说有笑,他又不由得既羡慕又嫉妒,希望自己能融入同学中去,成为他们中的一员。但是不知为什么,他总觉得与别人格格不入,似乎别人也不喜欢同他说话。为此,他开始沉迷于网络,经常上网,终日与网友聊天。
下面有关作者的表述不正确的一项是( )