Jimmy is always ______ for class. His teacher is not happy with him.
A:early
B:quickly
C:late
D:busy
下列关于基因、DNA和染色体关系的叙述中,错误的是( )
用课文原句填空。
某几何体的三视图如图所示,则此几何体是( )
读地球仪所表示的东半球经纬网示意图,各数字中均能够表示纬线的是( )