A:细胞核、染色体、DNA,基因
B:染色体、细胞核、基因、DNA
C:DNA,基因、细胞核、染色体
D:基因、DNA,染色体、细胞核
125×5____125÷5
515÷5____505÷5
840÷4____480÷4
420÷6____420÷2÷3
315÷3____720÷4
360÷3×2____360÷3÷2
A. What's the matter?
B. It's red and white.
C. Yes, it is! Thank you.
A: ____
B: I can't find my ball.
A: What colour is your ball?
B: ____
A: Look! Is this your ball?