脚手架扫地杆离立杆底部的距离为（ ）cm。
参考答案：T
下列反应中，是非氧化还原反应的是（ ）
①H2+Cl2点燃.2HCl
②Al2O3+2NaOH=2NaAlO2+H2O
③2HgO△.2Hg+O2↑
④CuO+2HNO3=Cu（NO3）2+H2O
⑤MnO2+4HCl△.MnCl2+Cl2↑+2H2O．
A．②④
B．①③
C．①②③
D．②④⑤
In the foreign trade business, the trade terms CFR is often used. CFR is the abbreviation for （）.
A. Commercial Invoice
B. Cost, insurance and freight
C. Cost and freight
D. Carriage paid to
