A.30° B.45° C.60° D.75°
A.一層至二層樓梯平臺(tái)上方某處 B.二層至三層樓梯平臺(tái)上方某處 C.二層樓板面處 D.二層樓面之上、二層至三層樓梯休息平臺(tái)之下某處
A.1:10 B.1:15 C.1:50 D.1:100