地球上产生四季的主要原因是[ ]
A、地球的自转
B、地球的不运动
C、地球的公转
D、板块运动
答案:C
Not everybody knows there ____ more than one kind of English in the world. [ ]
A. is
B. are
C. has
D. have
结核病分类是()
A.原发性肺结核
B.血行播散性肺结核
C.继发性肺结核
D.结核性胸膜炎
E.肺外结核