— John seems happy, even though his wife left him and he lost his job.

— I think he __________ to put on a brave face.

A．will try

B．has tried

C．had tried

D．is trying

[背景材料3]
某施工单位承接了一段二级公路施工，合同规定的主要工作项目有路基施工、沥青混凝土路面和一座小桥。其中路基工程的土方基本平衡，开挖量小，土方转运距离在70m左右。采用轮胎式摊铺机进行路面施工。
桥梁基础为钻孔桩基础，该处主要为卵石、漂石地质条件。
问题：

本路段桥梁基础施工宜采用( )进行钻孔作业。

A．螺旋钻机

B．冲击钻机

C．回转斗钻机

D．液压旋挖桩孔机