Most scientists seem to agree that ________ certain limit should be set on ______

sale of cars to ease air pollution.

A．a; the

B．/; the

C．the; /

D．the; the

下列命题是否具有相同的命题形式？为什么？“某罪犯或犯有走私罪，或犯有贪污罪”与“某罪犯既犯有走私罪，又犯有贪污罪”。