【判断题】The Venusian scientists will probably come to the conclusion that there is no life on Earth.
【单选题】Once he realizes that it is his mistake, Jim never ________ to admit and correct it.
【单选题】There isn't _______ tea in your cup. Would you like ________? [ ]
【判断题】晶体管的电流放大系数β越大越好。 ( )
【简答题】倒向晶体管的电流放大系数为什么小于正向晶体管的电流放大系数?
【判断题】一国的国际收支出现逆差,一般会引起本国货币汇率下浮。( )
【单选题】His friends and doctors very much ________ whether he could do it.
【简答题】晶体管的电流放大系数太小时,电流放大作用将 ;而电流放大系数太大时,又会使晶体管的性能 。
【简答题】设总体 的密度函数为 ,则 ____(填“是”与“不是”) 的无偏估计.