a、b、c三个α粒子由同一点垂直场强方向进入偏转电场，其轨迹如图所示，其中b恰好同时飞出电场，下列说法中不正确的是（   ）

亚非文明古国的共同特点是（   ）

①地处大河流域

②对外进行军事扩张

③以农业经济为主

④建立统一的奴隶制国家

⑤实行奴隶制民主政治

   Today we 1 only three lessons in the morning. The first lesson is math. It 2 at eight o’clock and finishes at 3 to nine. It is in Room 101. But I don’t like math. Then the second lesson is my favorite 4 —music. It starts at nine o'clock. The 5 lesson in the morning is PE. It starts at ten 6 ten and finishes at five to eleven. We have our lunch at eleven thirty 7 the second floor of dining hall. We have two lessons 8 lunch. Art starts at two and at three o'clock we have a 9 lesson. We can learn a lot of knowledge about China. At about four in the afternoon 10 is over.

下面不属于三江源地区的是（    ）