A：{1，2，3}
B：{2}
C：{1，3，4}
D：{4}
根据问句，选择最佳答案。
① Good morning. ____ A. Good morning.
② What do you see? ____ B. Yes, I like sweets.
③ Do you like sweets? ____ C. It's sunny.
④ What do you hear?____ D. I see a bee
⑤ How's the weather?____ E. I hear a sheep.
受精卵发育成为（ ）
