31.梁板式樓板主梁的經(jīng)濟跨度一般為(      )

A.3～5m                                                       B.4～6m

C.5～8m                                                        D.7～9m

32.下列樓梯中按用途劃分的是(      )

A.室內(nèi)樓梯                                                   B.雙跑梯

C.室外消防梯                                                D.剪刀梯

33.樓梯平臺寬度供單人通過時應不小于(      )

A.650mm                                                      B.750mm

C.850mm                                                       D.950mm

34.要使雨水容易排除，坡屋頂?shù)钠露纫话愦笥?      )

A.10％                                                          B.15％

C.20％                                                          D.25％

35.下列屬于平屋面無組織排水的是(      )

A.槽溝外排水                                                B.女兒墻外排水

C.由屋檐自由落到室外地面                           D.內(nèi)排水