Hỗn hợp 2 đồng vị có nguyên tử lượng trung bình là 79,9. Đồng vị 1 có số nơtron ít hơn đòng vị 2 là 2. Đồng vị 1 có % nguyên tử bằng 11/9 % nguyên tử của đồng vị 2. Xác định số khối mỗi đồng vị

Marcella left home very early because she wanted to be sure of catching the train(miss)

—>So

Patrick hadn’t heard from his uncle in Australia for over 5 years

—>It was

I/going/have/new house/build/next month.//

—>

Most/energy/we/use/electricity/which/produced/mainly/coal.//

—>

I/not want/go/work/own car/because/it/hard/find/somewhere/park.//

—>

Choose the option whose main stress is pronounced different from that of the rest

1.A.animals B.temperature C.population D.photograph

2.A.contribute B.investigate C.dependent D oversized

3.A.dangerous B.recycle C.polluted D.variety

4.A.conservation B.submarine C.environment D.employee

5.A.apologize B.congratulate C.introduce D.technology

Mng giúp em bài này với ạ, nếu được ghi cho em nhấn âm mấy luôn, huhuu em cảm ơn nhiều ạ

Our century has seen great changes in the life and living conditions of people. Less than a hundred years ago, many the things we(1)...now seemed impossible. No one could image that people could fly, or that we could listen to music thousands of miles away. Today, radio and television serve many purposes(2)...pleasure. They help us fish in the sea and land airplanes in bad weather or at night. They control the work of large(3)...of machine in industry. Never before in history have three been such rapid changes in our way of life as at the present moment. Scientists have been using what is known a scientific method to make new discoveries are new medicines. Many illnesses that people died(4)...50 years ago no longer dangerous. The study of science help us(5)...our outlook and opens a whole new world for us. The progress of science is leading to a better and better life for man.

1. A.make B.do C.get. D.conduct

2. A.despite B.in addition C.besides D.also

3. A.numbers B.amounts C.lots D.tasks

4. A.out B.in C.for D.from

5. A.open B.enlarge C.lengthen D.widen

Mng giúp em với ạ, nếu được ghi lí do luôn ạ. Em cảm ơn nhìu lắm ak :3

Ở Nhật Bản vận tải đường biển phát triển nhất, nguyên nhân chính là do:

Nhân tố quyết định nhất tới sự phân bố dân cư của vùng Đông Bắc Hoa Kì là

Nguyên nhân chủ yếu khiến tỉ lệ nam cao hơn nữ ở các nước Trung Quốc, Việt Nam là