“Have you seen _____ pen? I left it here this morning.” “Is it _____ black one? I found it in the corner.”

A．a, the

B．the, the

C．a, a

D．the, a

显影液中促进剂的作用是（）

A.维持显影液中pH相对稳定

B.防止污染

C.微粒显影

D.避免显影液氧化

E.促进坚膜过程