室内用花岗岩的（）进行复验。
A.吸水率
B.抗冻性
C.放射性
D.均匀性
参考答案：C
I worked on the problem ____ a long time and I worked it out ____ myself ____ last.[ ]
A. for; by; at
B. in; with; on
C. on; by; in
D. for; for; at the
