某商店进行降价促销活动，夹克每件28元，短裙每件50元，运动裤每件42元，皮鞋每双55元.妈妈有90元钱，想买上面的两件商品，她可以买哪两件？还剩多少钱？

    On a cold evening with snow floating in the air, I got ____ (stick) on the road because of a flat tire(轮胎). I attempted ____ (seek) help from the passing cars, but no one stopped. As I was about to give up hope, a man ____ (drive) an old dirty car came to my aid. To be honest, I was scared when he first approached me. Eying him up and down, I thought to myself, “There is a very good chance ____ he may rob me,” He seemed to have sensed my discomfort so he tried to ease my ____ (anxious) by introducing himself. His act of kindness made me feel ashamed to have questioned his intentions. ____ was really considerate of him to stop to help a perfect stranger like me, especially in such terrible weather. Thus, after the spare tire was fitted, I asked ____ much I owed him. I wanted to pay him back. ____ (surprising), he did not take my offer but rather told me to pass the act of kindness forward and help more people ____ need. As he said those words, I noticed him wearing a smile of contentment. Helping  others seemed a very ____（nature）thing to him. I witnessed the true beauty of human nature in him.

下列实验操作或事故处理中，正确的做法是　 ____（选填序号，选对1个得2分，选错1个倒扣2分）

A．银镜反应实验后附有银的试管，可用稀H₂SO₄清洗

B．在粗盐的提纯实验中，溶解、过滤、蒸发都用到了玻璃棒

C．不慎将浓硫酸沾在皮肤上，立即用NaOH溶液冲洗

D．配制FeCl₃溶液时，将FeCl₃固体溶于较浓盐酸中，然后再用水稀释到所需的浓度

E．在250mL烧杯中加入216mL水和24g NaOH固体，配制质量分数为10% NaOH溶液

F．不慎接触过多的氨，及时吸入新鲜的空气和水蒸气，并用大量水冲洗眼睛

G．用结晶法可以除去硝酸钾中混有的少量氯化钠

H．为了测定某溶液的pH，将用蒸馏水润湿的pH试纸浸入到待测溶液中，过一会取出，与标准比色卡进行对比．

化学方程式2Na₂O₂+2H₂O=4X+O₂↑中，X 的化学式为（   ）