—Sorry, you can't. Your father has to use it.

“六年前出去吃饭、购物基本都是付现金；三年前出去吃饭、购物基本都是刷卡；而现在出去吃饭、购物付款都是扫一扫”。对这种现象从经济生活角度理解正确的是（    ）

①纸币不断贬值，促使人们尽量减少现金使用

②结算方式的变化,使人们消费更加方便快捷

③消费结构的改善，说明我国居民的恩格尔系数下降

④生产发展科技进步，深刻影响着居民经济生活

根据短文内容，完成下面的任务。

Dear Grandma,

    How are you? I am very busy this month. (A)September 5th is my good friend Gina's birthday. I will go to her birthday party in the evening. On the eleventh, (B)我有一个英语测试. On September 17th, I have a baseball game. You know I love baseball. On the 24th, I have a school trip. On the 28th, I'll go to Mr. Cool's Clothes Store. The clothes there are on sale that day. I want to buy a pair of sports shoes and a T-shirt. The hats there are very nice. I will buy one ① ________ you. Oh, Grandma, I'm very sorry I can't go to see you ② ________ my parents this month. See you next month.

 Yours,

Eric

造成黄土高原水土流失的土质原因是（　　）