题目

西瓜的果实和种子分别是由花的什么结构发育而来    A.子房和胚珠      B.子房和受精卵    C.雌蕊和珠被      D.子房壁和受精卵 答案：A—Hello,Mr Cheng.This is Yang Mei.I'm caught in traffic,and won't make it on time.—________.We 'll wait for you. [     ]A. Cheer up       B. Go aheadC. That depends  D. That's all right