每个____都由一个个圆饼状的____结构____ 而成．这些囊状结构成为____．吸收光能的四种色素，就分布在类囊体的____ 上．
写出近义词
了解—____ 帮手—____ 自豪—____
When and where we'll hold the meeting ________ not been decided yet.
