A:∠1=∠2
B:∠3=∠4
C:∠BAC=∠BCD
D:∠ABC+∠BAD=180°
____ ____ Bill____for breakfast?
—Is your sleeping problem getting better? —No. And . They gave me the wrong medicine this time. Can you believe that?
①当升降机加速上升时,游客是处在失重状态
②当升降机减速下降时,游客是处在超重状态
③当升降机减速上升时,游客是处在失重状态
④当升降机加速下降时,游客是处在超重状态.