The selection of countries in this course is based on ____and ____activities.
____and ____have been left out because there is no ____.
马道的土石方量,需要时按每坑______m3另行计算;
A. 0.4
B. 0.6
C. 0.8
D. 1.0
当冻土厚度______时,冻土层的挖方量,按坚土挖方量进行计算,但应单独统计。
A. ≥300m
B. ≥200m
C. ≥100m
D. ≤300m