Food safety is a problem in all places around the world and people in different areas of the world prepare foods in different ways. The WHO released five simple rules for preparing food in a safe way.____

    Key 1: Keep clean.

    The first key tells about the importance of washing. People should wash their hands often—before touching food, while they are preparing food, and any time after they go to the toilet. People should wash all surfaces and equipment used for preparing food.____

    Key 2:____

    People should separate raw, or uncooked food from foods that are already cooked and foods that will not be cooked. People should store raw meat, chicken, and fish in containers, or in separate areas. Raw foods should not touch prepared foods.

    Key 3: Cook completely.

    People should cook eggs and meat, like birds, seafood, and animals, especially carefully. These foods may carry more micro-organisms than other foods. Food like soup must be boiled for at least a minute to make it be cooked completely. It is also important that people re-heat cooked food completely.

    Key 4: Keep food at safe temperatures.

    When people are finished with eating, they should keep the left food in a refrigerator below 5℃ and shouldn't store it for too long. At room temperature, about 20℃, the amount of micro-organisms can increase very quickly.____They cannot grow as quickly in a very hot or very cold environment.

    Key 5: Use safe water and raw materials.

    ____ Damaged or old food may develop harmful chemicals as it gets older.

A. Eat cooked food immediately, while it is still hot.

B. They call these rules the “Five Keys to Safer Food.”

C. Separate raw and cooked.

D. People should use safe water and choose fresh foods.

E. Keeping everything clean helps people to avoid micro-organisms.

F. People should also protect cooking areas and food from insects and animals.

G. But temperatures above 60℃ or below 5℃ control the growth of micro-organisms.

①C、N、O的电负性由大到小的顺序为____．

②写出Cu的核外电子排布式____．

③化合物Cu（NH₃）₃（CO）Ac中，金属元素的化合价为____．

④在一定条件下NH₃和CO₂能合成尿素CO（NH₂）₂，尿素中C原子轨道的杂化类型为____；1mol尿素分子中，σ 键的数目为____．

⑤Cu₂O晶体的晶胞结构如图所示，若阿伏伽德罗常数为N_A，晶胞的边长为a pm，则晶体的密度为____ g•cm^﹣3．

    Man has been interested in robots for quite some time. Scientists are always inventing new and good robots, which will play an important role in our future lives.

    ____

    They will take over jobs such as preparing meals, washing dishes, and sweeping the floor, so that we will have more free time to have fun.

    ____

    They will do all the heavy and dangerous work, and be put in hospitals, schools and offices.

    ____

    Whenever we feel sad, lonely or upset, we can have a chat with a robot. Robots will not only be good friends but they will also offer us good advice.

    In conclusion, robots will be more and more intelligent and will benefit us in many ways.

A. Robots will be our friends.

B. Robots will help us with our work.

C. Robots will be of help in doing housework.

D. Robots will replace humans in many ways.

仿照下面的例句写一句话，要求与例句格式相似，并运用比喻等修辞手法。

例句：我不是挺立在高山峻岭中的巨松，而是辽阔草原上的一棵小草——为壮丽的河山添上一笔绿意。

仿写：