Would you please tell me________to deal with all the problems, Mr Feng?
A:how
B:why
C:what
D:which
如图,在△ABC,AB=AC,∠A=70°.求∠B和∠C的度数.
细菌在细胞结构上区别于植物细胞的特点主要是( )
①有细胞壁 ②没有叶绿体 ③没有成形的细胞核 ④有鞭毛.