如图,四边形ABCD内接于⊙O,若四边形ABCD的外角∠DCE=70°,则∠BAD的度数为( )
A:140°
B:110°
C:220°
D:70°
植物叶片在阳光下进行光合作用的产物主要是( )
It is many years since we began to enjoy a _______ spring holiday each year.
战国七雄是指齐、楚、燕、韩、晋、魏、秦。