下列语句中，反映长江流域已成为我国古代经济重心的是（    ）

将要成熟的大豆豆荚加工成的菜肴，俗称“毛豆”．在栽培过程中因某种因素引起花粉发育不良，影响传粉受精，如果要保证产量，可采用的补救方法是（　　）

    Hello, I'm Kate. This is a photo of my aunt's family. The woman in the photo is my aunt, Jane. She is a teacher and she is very kind（善良）. These are my cousins Jeff and Jack. They are seven and they are twins. Look! That lovely baby is my aunt's little daughter, Rose. She is only one. I love them very much.