We don’t think the experiment is _______ failure. At least we have gained _______ experience for future success.

A．the; a

B．a; an

C．a; /

D．/; the

混凝土中粉煤灰掺量大于30%时，混凝土的水胶比不得大于（）；预应力混凝土以及处于冻融环境的混凝土中粉煤灰的掺量不宜大于（）%。