工作内容复杂、投资额大的咨询项目、咨询服务的采购方式是( )。

A．有限竞争性招标
B．竞争性招标
C．直接谈判采购
D．邀请招标

I regret to have not paid more attention to our English lessons at school.

A．not paying

B．not having paid

C．have not paid

D．not to have paid