问题详情

Which of the following prepositional phrases is an adverbial of concession？

A．With all his boasting, Robert achieved very little.

B．Firebricks(耐火砖)are used with the object of minimizing heat losses in the boiler(锅炉).

C．She fell down the stairs with all her shopping.

D．He sewed on the button with considerable awkwardness.

请帮忙给出正确答案和分析，谢谢！