— How do you find the lecture by Mr. Lee?  

— _____.   [ ]

A. It's a fine day.                          

B. Very boring        

C. In the conference hall                    

D. By bicycle

适用于极软地层的牙轮钻头的布置方案是（）。

A、自洗移轴式布置

B、非自洗式布置

C、自洗不移轴式布置

D、不确定