zǔ xiān
shì jiè
fǎn fù
jiān nán
____
—How many ________ are there on the table?
—Three. Are you thirsty? Let's cut one and eat it.
吃西瓜消暑是一件很惬意的事情，西瓜的果实和种子分别是由什么结构发育而来( )
