During the construction of the Beijing-Zhangjiakou Railway, Jeme Tien Yow________.
选项：

A:felt ashamed for the work relied on foreigners
B:used Rackarock for the first time in the excavation of caves
C:decided to dig two shafts above Badaling Tunnel and then excavated to both ends to form six excavation faces to accelerate the progress of the project
D:reduced the cost of the project greatly and completed the construction as scheduled