A.(墻長-100)/間距向上取整+1 B.(墻長-50)/間距向上取整+1 C.(墻長-s)/間距向上取整+1 D.(墻長-s)/間距向上取整
A.洞口寬-2*100 B.洞口寬-2*50 C.洞口寬-S D.洞口寬
A.50mm B.100mm C.S/2 D.500mm