两种学习之间的相互干扰、阻碍叫做( )。
A. 正迁移
B. 负迁移
C. 水平迁移
D. 垂直迁移
良种肉用牛西门塔尔牛的形体特征是( )。
A. 有白色条斑绒毛
B. 通体绒毛为黑色
C. 体型较短
D. 胸肩部肌肉发达
I ______letters from my daughter since she left.
A. don't receive
B. haven't received
C. didn't receive
Which one do you like ______, this hat or that one
A. better
B. best
C. well