小明同学想利用日常生活用品进行化学学习和探究活动，食盐、食醋、纯碱等均为厨房中常用的物质，利用这些物质小明能完成的实验是

①洗涤餐具上的油污

②用食盐水洗去菜刀表面的铁锈

③用化学方法鉴别食盐和纯碱

④除去热水瓶中的水垢[ ]

A．①②③

B．①③④

C．②③④

D．②④

The project is not going well and many changes are being made. Which of the following should you do FIRST to gain control of the project

A) Review the scope of work with the stakeholders.
B) Create a new change form.
C) Remind everyone of the change procedures.
D) Ask management for help.