玲玲给大明写了一封信，根据括号内汉语提示请你帮助玲玲把信补充完整。

Dear Daming,

    Today I __ l___ to the supermarket (起市). I bought a hat  __2___ my mother. It is (漂亮). But I think

it is too     _4___ (大). I want to  __5__  (买) you a gift. What do you want? Please tell me.

Yours,

Lingling

存在于自然界的氨基酸有300余种，但组成蛋白质的只有20种。