【简答题】完成表格(注意:一空可填多词) In 30 years from now, what will we cat? Will the food still, be the same as it is now? The United Nations says that there will be over 9 billion people in the world by 2050. Our food n...
【简答题】Apart from buying a few items that will help him/ her look like a native, what else is a solo traveler supposed to do in order to blend in with the local surroundings?
【简答题】听下面一段材料,回答第1-2题。 1. What present will the speakers get for Jessica’s birthday? A. A basketball. B. A Barbie doll. C. A cat. 2. What does the woman ask the man do? A. Not to tell anyone else. B. Forget...
【简答题】放大电路如图 E.7 所示 , 已知 R B1 = 22 k Ω , R B2 = 9 k Ω , R C = 2 k Ω , R E = 2 k Ω , R L = 2.5 k Ω , U CC = 12 V, 晶体管的输入电阻 r be = 1 k Ω , 电流放大系数 =50, 按要求回答:(1)求 静态工作点 (2)当电路接近截止状态时,为了避免波形失真,电路的参数 R B2 应如何调整。
【简答题】放大电路如图 E.7 所示, 晶体管的电流放大系数 , U BE = 0.6V , R B1 = 10 k W , R B2 = 5 k W , R C = 2 k W , R E = 1 k W , R L = 6 k W , r be = 6 1 k W 。 按 要求回答:( 1 )求放大电路的输入电阻和电压放大倍数。( 2 )当空载时,与( 1 )比较, A u 如何变化? ( 3 )如果该...