M: No, I don't.
①接受信号分子的刺激 ②运输 ③与核酸结合,维持核酸的稳定
④催化作用 ⑤作为激素,起调节作用 ⑥作为信号分子.
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?