—Why do you always lie to our mother you love her cooking?

—It's only a white lie, so _______．

A．don't bother

B．my pleasure

C．it's no big deal

D．mention it

锚索安装48小时后，如发现预紧力下降，必须及时补拉。张拉时如发现锚固不合格，必须（）。

A、补打合格的锚索

B、补打锚杆

C、打点柱