Một ô tô chuyển động từ A đén B. Trong nữa đoạn đường đầu, xe chuyển động với tốc độ 14m/s. Trong nữa đoạn đường sau xe chuyển động với tốc độ 16m/s. Hỏi tốc độ trung bình của xe trên cả đoạn đường là bao nhiêu?

Giúp em với ạ!:3

Valentine's s Day is always on Fedruary 14. It's not a national day. On weekdays, schools are open. Banks are open. People go to work. Life goes on as usual, but the there is one difference. People give cards and gifts to friends and people they love. They say, " Be my Valentine".

There are many kinds of Valentine cards. Some people make cards. Most people buy them. Men and women often give each other romantic cards. These cards say, "I love you". The husbands give romantic cards to their wives.

Children and friends usually give funny or humorous cards. These cards do not say, " I love you". They are not romantic. Children give cards to their friends at school parties.

Flowers and candies are popular gifts on Valentine's Day. Many people give red roses to people they love. Stores sell chocolates and other candies in heart shapes.

Questions

1. When is Valentine's Day?

2. Do children give cards to their friends at school parties?

3. How many kinds of Valentine cards are there?

4. Who gives romantic cards to their wives?

Valentine's s Day is always on Fedruary 14. It's not a national day. On weekdays, schools are open. Banks are open. People go to work. Life goes on as usual, but the there is one difference. People give cards and gifts to friends and people they love. They say, " Be my Valentine".

There are many kinds of Valentine cards. Some people make cards. Most people buy them. Men and women often give each other romantic cards. These cards say, "I love you". The husbands give romantic cards to their wives.

Children and friends usually give funny or humorous cards. These cards do not say, " I love you". They are not romantic. Children give cards to their friends at school parties.

Flowers and candies are popular gifts on Valentine's Day. Many people give red roses to people they love. Stores sell chocolates and other candies in heart shapes.

Questions

1. When is Valentine's Day?

2. Do children give cards to their friends at school parties?

3. How many kinds of Valentine cards are there?

4. Who gives romantic cards to their wives?

Valentine's s Day is always on Fedruary 14. It's not a national day. On weekdays, schools are open. Banks are open. People go to work. Life goes on as usual, but the there is one difference. People give cards and gifts to friends and people they love. They say, " Be my Valentine".

There are many kinds of Valentine cards. Some people make cards. Most people buy them. Men and women often give each other romantic cards. These cards say, "I love you". The husbands give romantic cards to their wives.

Children and friends usually give funny or humorous cards. These cards do not say, " I love you". They are not romantic. Children give cards to their friends at school parties.

Flowers and candies are popular gifts on Valentine's Day. Many people give red roses to people they love. Stores sell chocolates and other candies in heart shapes.

Questions

1. When is Valentine's Day?

2. Do children give cards to their friends at school parties?

3. How many kinds of Valentine cards are there?

4. Who gives romantic cards to their wives?

Giúp em với ạ

In Britain, natural gas is the most popular fuel for heating homes, and for cooking. It is piped all over the country from the gas fields below the North sea. Natural gas is used chiefly as a direct source of energy, although it is also used in the chemical industry. At the moment, the supply is plentiful, but it will be running short by the end of the century, and it will run out during the 21st century unless new supplies are found. We could do without natural gas, as coal gas can be used as a substitute, and there should be enough coal to last for several centuries. However, it is a form of energy which is not only cheap, but also highly efficient.

Questions

1. Where does natural gas come from?

2. When will it run out?

3. Is it efficient?

4. What can be used as a substitute for natural gas?