She _____ the park every day.[ ]
A. is going
B. goes
C. visits
D. is visiting
答案:C
— ____ you sing the English song?
— Yes, I can.
A.Can
B.May
C.Must
D.Need
性别、种族、籍贯、血型、个性特征等因素,在实验研究中一般可以作为()。
A.自变量
B.无关变量
C.分类变量
D.独立变量