Lucy has changed a lot since she got her new job. Recently she ________ her work quite well.

A．has been doing

B．has done

C．did

D．had done

公路桥梁中的其他可变荷载包括（）、支座摩阻力和温度影响力等。

A.人群荷载

B.漂浮物的撞击力

C.汽车制动力

D.地震力