如图,AB是⊙O的直径,点C、D在⊙O上,AD∥OC且∠ODA=55°,则∠BOC等于( )
A:105°
B:115°
C:125°
D:135°
①废除农奴制度
②设立议会机构
③建立近代工业
④挽救民族危机
We are ____ (concern) about the continuing pollution of the environment.