6kV=________V，2.2MΩ=________Ω，家庭电路的电压是_________V。
6000；2.2×106；220
每皮中丁砖与顺砖相隔，上皮丁砖坐中于下皮顺砖，上下皮相互错开1／4砖长，此种组砌形式是（）。
A.一顺一丁
B.三顺一丁
C.梅花丁
D.全丁
A company issued a bond with a face value of $ 67831, maturity of 4 years, and 7 percent coupon, while the market interest rates are 8 percent. What is the unamortized discount when the bonds are issued
A．
B．
C．
