When ____ to feel unworthy, children often work extra hard to please their parents．

A．to make

B．making

C．made

D．having made

所谓“异地加工贸易”，是指加工贸易企业将保税料件加工的产品结转至另一直属海关关区内的加工贸易企业深加工后复出口的经营活动。（）