I would like to play with you, _______ I have to do my homework first.
A:or
B:so
C:and
D:but
读图,京沪高速铁路连接了我国两大工业基地( )
实验室通常用MnO2和浓盐酸共热制取Cl2,反应的化学方程式为MnO2+4HCl(浓) △__ MnCl2+Cl2↑+2H2O.