菌种选育通过四个步骤完成:()、()、纯种分离和生产性能测定。
参考答案:样品采集;增殖培养
除去SO2中混有的HCl气体,可选用的试剂是
A.石灰水
B.浓硫酸
C.饱和NaHSO3溶液
D饱和Na2SO3溶液
Look! ______ Some fish on the table, and some apples ______ in the box. [ ]
A. is; are
B. are; is
C. are; are
D. is; is