钢筋的理论重量根据什么计算最合理？
参考答案：根据铁的比重，用参数算法不精确。
自我呈现理论
Out of the crowded bus _____, who was wearing a pair of dark glasses. [ ]
A. stepped a tall man in his thirties
B. a tall man in his thirties stepped
C. did a tall man step in his thirties
D. did a tall man in his thirties step
