化学

旁白 neutral

Arsenic is a toxic element commonly found in certain types of rock and soil

砷是一种有毒元素，常见于某些类型的岩石和土壤中。

旁白 neutral

Calcium is essential for maintaining strong bones and teeth in the human body

钙对维持人体强壮的骨骼和牙齿至关重要。

旁白 neutral

Carbon is the fundamental element for all known life forms on Earth

碳是地球上所有已知生命形式的基本元素。

旁白 neutral

Copper is a good conductor of electricity and widely used in electrical wiring

铜是良好的导电体，广泛用于电线中。

旁白 neutral

Helium is used to inflate balloons because it is lighter than air

氦气因比空气轻，被用来给气球充气。

旁白 neutral

Gold has been valued as a precious metal for centuries and used in jewelry and currency

几个世纪以来，黄金一直被视为贵金属，用于珠宝和货币。

旁白 neutral

Iron deficiency can lead to anemia , a common blood disorder

缺铁会导致贫血，这是一种常见的血液疾病。

旁白 neutral

The tour guide will lead us through the historic district to explore its landmarks

导游将带领我们穿过历史街区，探索其地标。

旁白 neutral

Vinegar has an acid taste and is often used in cooking to add flavor

醋有酸味，常用于烹饪中增添风味。

旁白 neutral

Enzymes act as catalysts in biological reactions , speeding up chemical processes

酶在生物反应中起催化剂作用，加速化学反应进程。

旁白 neutral

Chemical reactions can transform one substance into another with different properties

化学反应可以将一种物质转化为具有不同性质的另一种物质。

旁白 neutral

Oxygen is a key element required for human respiration

氧气是人类呼吸所需的关键元素。

旁白 neutral

Water is a compound made up of hydrogen and oxygen atoms

水是由氢原子和氧原子组成的化合物。

旁白 neutral

Some skincare products contain hydrates to help moisturize the skin

一些护肤品含有水合物，有助于滋润皮肤。

旁白 neutral

Air is a mixture of nitrogen , oxygen , and other gases

空气是氮气、氧气和其他气体的混合物。

旁白 neutral

Activated carbon can adsorb impurities from water , making it cleaner

活性炭可以吸附水中的杂质，使其更洁净。

旁白 neutral

A balanced diet should include a variety of fruits , vegetables , and proteins

均衡的饮食应包括各种水果、蔬菜和蛋白质。

旁白 neutral

How a substance behaves in different environments can be studied through experiments

可以通过实验研究一种物质在不同环境中的表现。

旁白 neutral

Chemical bonds hold atoms together to form molecules

化学键将原子结合在一起形成分子。

旁白 neutral

Certain metals can catalyze the decomposition of hydrogen peroxide

某些金属可以催化过氧化氢的分解。

旁白 neutral

chain reaction

n. 连锁反应

旁白 neutral

A nuclear chain reaction releases a large amount of energy in atomic bombs

核连锁反应在原子弹中释放出大量能量。

旁白 neutral

chemical reaction

n. [化学] 化学反应

旁白 neutral

Burning wood is a chemical reaction that produces heat , light , and carbon dioxide

燃烧木材是一种产生热、光和二氧化碳的化学反应。

旁白 neutral

Prolonged exposure to the sun can dehydrate the body , leading to heatstroke

长时间暴露在阳光下会使身体脱水，导致中暑。

旁白 neutral

Water can be distilled to remove impurities and make it safe for drinking

水可以通过蒸馏去除杂质，使其安全饮用。

旁白 neutral

The chemical equation shows the reactants and products of a reaction

化学方程式显示了反应的反应物和生成物。

旁白 neutral

The formula for calculating density is mass divided by volume

计算密度的公式是质量除以体积。

旁白 neutral

Adding a reagent can precipitate the metal ions from the solution

加入一种试剂可以使溶液中的金属离子沉淀。

旁白 neutral

Refrigeration is a common method for the preservation of food

冷藏是一种常见的食品保存方法。

旁白 neutral

The body's immune reaction to an infection may cause fever and inflammation

身体对感染的免疫反应可能导致发烧和炎症。

旁白 neutral

Aluminum is a lightweight metal used in the production of cans and aircraft parts

铝是一种轻金属，用于生产罐头和飞机零部件。