单项选择题 W: Did you watch the 7 o’lock program on channel 2 yesterday evening?1 was about to watch it when someone came to see me.M: Yeah!It reported some major breakthroughs in cancer research. People over 40 would find a program worth watching.Q: What do we learn from the conversation about the TV program?（）

单项选择题 公称直径为600mm的液体管道在压力试验合格后应进行吹洗工作，正确的做法是（）。

单项选择题 纳税期限是指纳税人将应纳税款缴入国库的期限。( )