标定HCL溶液常用的基准物有（）和（），滴定时应选用在（）范围内变色。

分解因式：m²-2m=______．

镁、铁在日常生活中有较为广泛的用途。如：

（1）镁在空气中燃烧时，发出耀眼的白光，可用来制造镁闪光灯，其反应化学方程式为：   。

（2）市场上出售的补血麦片中常含有微量颗粒细小的还原性铁粉，铁粉与人体胃液中的盐酸反应转化成氯化亚铁，起到补血作用，写出这个反应方程式：      。

Expressing gratitude is an important form of good manners. Nowadays more and more people in China have found it’s high time to (1) a thankful heart for the young.Everyone likes to get praised and appreciated. Gratitude is the greatest of virtues, which lets others smile and makes the world more beautiful. You just need several minutes to write down a thank-you note, but it brings much joy to the (2) .We live in a society where we enjoy the different services of others. But (3) of them should be taken for granted.Gratitude is also a kind of (4) in life. In developing gratitude for every moment—for the simple joys and even for the (5) times—we come to truly enjoy and appreciate life. Then we are able to see the (6) that surrounds us.Try to write a thank-you letter to your parents for working hard to (7) you a happy life.Be grateful to your teachers because of their (8) with your studies and character building.Say thanks to your friends who (9) both your happiness and sorrow. We are sure it will bring them much joy and add (10) into your own life as well.

第（8）空应选择（）

A．study

B．part

C．help

D．cooperation

心外膜就是（）.

A、纤维性心包

B、浆膜性心包壁层

C、浆膜性心包脏层

2000版准运证第二联用于（）。

A、存根

B、交承运单位

C、随货同行

D、交托运人