【单选题】China is famous ______ the Great Wall. [ ]
【单选题】China is famous _____ its tea. [ ]
【简答题】产生异方差的原因是什么?试举例说明经济现象中的异方差性。
【简答题】什么是异方差性?举例说明经济现象中的异方差性。检验异方差性的方法思路是什么?
【简答题】在普通车床上用两顶尖装夹车长轴外圆,若机床刚度较低,则工件产生()的形状误差;若工件刚度较低,则工件产生()的误差。
【单选题】 Joe was caught in a traffic jam and when he got to the theatre, the play ________ for half an hour.
D.
had already been put on
【单选题】China is famous ______its food in the world.