印花税由纳税人根据税法规定，自行计算应纳税额，自行购买印花税税票，自行完成纳税义务。( )
参考答案：对
— Why didn't you call him yesterday?
— I him ,but the line was busy. [ ]
A. do call
B. did call
C. was calling
D. had called
氟能抑制细菌摄入葡萄糖，从而
A．增加胞外多糖的合成和胞内多糖的贮存
B．增加胞外多糖的合成，抑制胞内多糖的贮存
C．抑制胞外多糖的合成，增加胞内多糖的贮存
D．抑制胞外多糖的合成和胞内多糖的贮存
E．不影响胞外多糖的合成和胞内多糖的贮存
