—Yes. You needn't worry about it.
A:which; has done
B:which; doing
C:that; has done
D:that; done
如图,在△ABC中,AB=BC,∠ABC=90°,BM是AC边中线,点D,E分别在边AC和BC上,DB=DE,EF⊥AC于点F,以下结论:
(1)∠DBM=∠CDE; (2)S△BDE<S四边形BMFE;(3)CD•EN=BN•BD; (4)AC=2DF.其中正确结论的个数是( )
对下列词语作解释。
畸形:____ 。
被誉为杂交水稻之父的是( )
下列变形正确的是( )