A:6m
B:12m
C:8m
D:10m
四大洋中,面积最大的是( )
盐城张老汉是个普通农民,1978年以后他所种的粮食可以这样分配( )
染色体结构的改变,会使排列在染色体上的基因的____ 或排列顺序发生改变而导致性状的改变.
圆x2a2+y2b2=1a>b>0的左、右顶点分别是A,B,左、右焦点分别是F1,F2若AF1,F1F2,F1B成等比数列,则此椭圆的离心率为 ( )
It's six o'clock in the afternoon. It's time for 1!Jenny and Li Ming are2. Jenny's mother is 3 in the kitchen. Jenny and Li Ming help Mrs. Smith 4 the vegetables. After dinner, Mrs. Smith washes the 5 dishes. Li Ming dries the dishes.