Đặc điểm chủ yếu để phân biệt lớp Hai lá mầm với lớp Một lá mầm ở số lá mầm của phôi: Cây Hai lá mầm thì phôi có 2 lá mầm, còn cây Một lá mầm thì phôi có 1 lá mầm.

+ Lớp một lá mầm : Phôi có 1 lá mầm, hầu hết có rễ chùm, thân cỏ. Gân lá có hình cung hoặc song song

+ Lớp hai lá mầm: PHôi có 2 lá mầm,  Hầu hết có rễ cọc, thân gỗ, thân cỏ, thân leo. Gân lá có hình dạng

Biển có vai trò rất quan trọng đối với sự phát triển và an ninh của các nước có biển nói riêng và của thế giới nói chung. Một số nước và vùng lãnh thổ đã lợi dụng thế mạnh về biển đạt trình độ phát triển kinh tế rất cao. 

Biển là kho nước vô tận, cung cấp cho các lục địa một lượng hơi nước rất lớn, sinh ra mây mưa để duy trì cuộc sống của con người, sinh vật trên Trái Đất và có tác dụng điều hoà khí hậu.

Biển còn là kho tài nguyên, thực phẩm vô cùng quý giá.

a.    Thể tích bể nước hình hộp chữ nhật là:

3*2*1,5=9m

Đổi 9m=90dm=90l

Trong bể có số nước là:

90/100*80=72l

b.     Đổi 72l=72dm=7,2m   

 Mực nước trong bể cao là:

7,2/3/2=1,2m

    ĐS:a.72 lít nước

         b.1,2 mét

Vì một số nơi nhiệt độ thấp hơn hoặc bằng nhiệt độ đông đặc của nước nên nước bị đông lại, không đo được, hơn nữa nước giãn nở không đều và lại trong suốt, rất khó nhìn ==> người ta không dùng nước để làm nhiệt kế đo nhiệt độ không khí

  Cảnh chợ Tết cuối năm nhộn nhịp, đông vui, và dường như em đã cảm nhận đuợc cái không khí đầu xuân. Mọi vật ở quê em và cả đất nứơc đang thay đổi, đang cởi bỏ chiếc áo cũ kĩ và chuận bị khoác trên mình một tấm áo khác đẹp hơn, để đón một cái Tết cổ truyền thật vui vẻ và đón một mùa xuân ấm áp đang trở về

have celebrated / celebration

Everything is two-faced like the two faces of a coin, and so is watching TV. Watching TV has advantages.

First, it widens our knowledge. Information on TV is diverse, letting the viewers know upto-date news from all fields of life such as news about politics, socioeconomy, scientific- chnology, etc…

Second, TV serves us as a means of relaxation. Films, plays, music shows on TV are vailable all day. We can enjoy these programs at home whenever we like.

Third, it is a good friend helping us kill time. Whenever we feel bored or do not know what to do. Simply turn on your TV set and you will surely feel OK soon. On the other hand, watching TV also has some disadvantages. Bad contents such as violent films, sexual exposures on the screen, and other sensitive topics may dangerously affect children. In addition, Watching TV too much or regularly also takes us much time and badly affects our health, especially our eyes.

Finally, we have to pay some extra money for electricity consumption, too. In short, watching TV, which may be good or bad, depends on the way we use TV to serve our life.

I very like watching cartoons. And of all the film I have seen, “Grave of the fireflies” is one in the cartoons which I like most. In Vietnamese it’s called is “Căn hầm đom đóm” or “Mộ đom đóm”. It’s a tragic story about two childents in the war. It’s made from Japan by Ghibli studio, directed and written by Takahata Isao. It is based on a nover of Nosaka Akiyuki. It’s written as a apologize to his sister. With Japanese, this film is understaned as a fable about the respect. Film is been in historical background at the end of the seconds world war from Japan. Film tells a painful story but moving to brothers sentiment of two orphaneds : Seita and Setsuko. They lost mother after a fierce bombing of American air force to Kobe city while their father combat for Japanese navy. So Seita and Setsuko must to struggle to exist between the famine and the resistance to merciless of surrounding people (that have their kinship). They have to live in a shelter-pit and often eat frogs and lizards. At the end, Setsuko have to die for hunger, pictures depict painfulness and the death of little girl can be considered as the most mournful film pictures in the cartoon Japan history. When everybody, who had seen this film are asked, most of them said they cried, and that have me.

My Favourite Sport is Swimming

Swimming has been my favourite sport since I was very small. I learnt to swim when I was just 5 years old. Swimming is a very popular sport; furthermore, it provides individuals with several physical and mental benefits.

There are some reasons why swimming is popular. Firstly, swimming is a sport for all age groups; besides, it is a lifetime activity. People can learn to swim as young as 4 or 5 years old or as old as 60 or 70. All it takes is the right instruction and desire to get in the pool. Secondly, swimming is cheap. You don't have to spend much money on it. All you need is just a swimsuit that makes you feel comfortable and a goggle that keeps water from your eyes. Even though you have to buy an admission ticket, it is not so expensive. Anyone can afford to go to swim. Finally, swimming is one of the most popular sports in the world.

Besides its popularity, swimming is a good activity that provides individuals with several physical benefits. First of all, swimming is a movement through water using one's legs and arms that provides an all body workout. As all of your muscles are used during swimming, it is an excellent form of exercise. Moreover, swimming can also be very beneficial to your heart and lungs. After a few laps, swimming can Giúp you cool-down, move blood through your muscles to Giúp them recover. Swimming builds up muscle strength , so your body is kept in perfect shape.

In addition to its physical benefits, swimming is also an effective way to relax. Swim with a very low effort, let your mind wander, focus on nothing but the rhythm of your stroke. This form of meditation can Giúp you gain a feeling of well-being. Furthermore, swimming is a wonderful recreational activity for you and your family. Swimming gives you a chance to be with your family or with some friends at the pool, or just to dip yourself in cool water. Spending hours at the pool on hot summer days is always my favourite pastime.

In conclusion, swimming is not only popular, but it is also one of the best all body workout a person can do. Besides its physical benefits, swimming is also a great recreational sport giving you peace of mind to continue with your day. Swimming has numerous advantages over other exercises and if done consistently will keep you in shape for the long period of time.