A：人造地球卫星的轨道可以与地球表面上某一纬度线(非赤道)是共面同心圆
B：第一宇宙速度是人造卫星绕地球运行所需的最大发射速度
C：地球同步卫星的高度和速率是确定的值
D：宇宙飞船进入轨道做匀速圆周运动时，飞船内的物体处于平衡状态，即合外力为零
下列各选项中“却”解释错误的一项是（ ）
My name is Jim. I am a student. At school, I have a good friend. His name is Mike. He is tall. He has short hair. We are classmates, too. We go to school at 7:00 o'clock. We go home at 5:00. It's 3:15 now. It's time to play games. Let's go to the playground. We play football with some boys. Jim and Mike are 。
已知关于x的一元二次方程x2+(m+3)x+m+1=0．⑴求证：无论m取何值，原方程总有两个不相等的实数根；⑵若x1，x2是原方程的两根，且x1-x2=22，求m的值，并求出此时方程的两根．
