Task 13

1 D

2 C

Task 14

1 - B

2 - D

Task 15

1 B

Task 21

1 A với C giống

2 A

Task 22

1 Van Gogh’s paintings arre almost as expensive as the work of Picasso

2 We didn't known the Recycled Orchestra until we watched the video online yesterday

1. B

2. C

b c

 1B

2C

1,B

2,D

3,D

4,A

1,B

2,A

3,C

4,D

Task 15

1 B

2 D

3 A

4 A

Task 16

1 B

2 A

3 C

4 D

b d a a b a c d

1 trang web dành cho học toán olm.vn

online math

yahoo hỏi đáp

hocmai

6/7 hỏi đáp

online ngữ văn

..

Ngoài hoc24, theo mình biết thì có trang OLM học toán, lop6/7 dành cho các bạn học sinh THCS, hocmai có các chương trình ôn, luyện thi, thi thử đại học trực tuyến, dành cho học sinh trung học phổ thông và trung học cơ sở; một số trang học tiếng anh như tienganh123, hellochao, duolingo, lingvist, busuu, learnenglishbritishcouncil.... Nói chung là có khá nhiều trang học trực tuyến, bạn thấy trang thích hợp với bạn thì vô đó học ;)

người đó đến lúc : 11 giờ nha

đến b lúc:

7h45p+2h50p-25=10h10p

SAI THÌ MK SR NHA^^

chị Tâm phải cộng cả thời gian dừng nữa

hay đấy/cảm ơn bn/thanks kìu véry mất

nhưng nó nói về cái gì ?

Mk vô rùi về 12 cung hoàng đạo

Enviroment is neccessary thing for this life. Enviroment is the air we breath, the water people drink and is everything they need for their life. But now the most important thing for the life is being polluted. This pollution affects the health of all living things. Air is damaged by lorry fumes and car, and power stations create acid rain which can destroys entire lakes and forests. When fossil fuels: gas, oil and coal are burned to provide energy for cooking, lighting etc. they form polluting gases. Not only on land but also in the sea, oils spills pollute sea water and kill marine life; chemical waste from sewage works and factories, and artificial fertilisers from farmland, pollute river water, spreading disease, and killing wildlife. Everything is being caused by human’s existence. Humans create rubbish! Each household produces about one tonne of rubbish each year! Most of this is taken away by dustmen and burned in incinerators or buried in enormous landfill sites – both of these actions can be dangerous for our environment.

But only people can change and solve it. Pollution could be prevented by all thing we do each day. First people can use recycled paper to save trees. Second try to avoid using plas. It is hard to recycle. People should refuse to use carrier bags. If people can not avoid buying plas bags, they should use re-use plas bags many times. Finally people must take their old clothes to charity shops. People also should save energy to protect environment. Switching off all electric things when they are not in use, walk or use a bicycle instead of car for short trips, keep healthy life and  keep clean atmosphere.

Keep clean environment isn’t only all ways are mentioned before but also to protect natural resources. That is the way to conserver wild life. First we need to conserve the old forest, rainforest, build more safari and national park, and plant more trees to make place to live for wild animals. Second we need to prohibit hunters who hunt animals too many out of the law allowance.

Finally, we now know that enviroment is the most important thing for life and we know how to protect and use it scientifically. Everyday we invent and find more and more way to protect enviroment. I hope that in the future the earth will be cleaner.

Gọi khối lượng giấy lớp 7A1 là a

khối lượng giấy lớp 7A2 là b

Áp dụng tính chất của dãy tỉ số bằng nhau, ta được:

\(\dfrac{a}{3}=\dfrac{b}{4}=\dfrac{b-a}{4-3}=23\)

Do đó: a=69; b=92