A:铁与盐酸反应
B:C与CO2共热
C:碳酸钙的分解
D:Ba(OH)2·8H2O晶体与NH4Cl晶体反应
There is ________ ‘h’ in the word ‘ghost’, but the ‘h’ doesn't make _________sound.
如图,AB=AC,AD=AE,DE=BC,且∠BAD=∠CAE.
(1)求证:△ABE≌△ACD;
(2)求证:四边形BCDE是矩形.