Hãy trình bày cách vẽ, cách cắt kiểu cổ tròn cơ bản

Thí nghiệm nào sau đây có khí thoát ra?

A. Cho miếng Fe vào dung dịch HNO₃ đặc nguội rồi nhấc ra nhúng vào dung dịch HCl

B. Cho bột Cr vào dung dịch NaOH loãng

C. Cho Si vào dung dịch NaOH loãng

D. Đổ dung dịch BaCl₂ vào dung dịch H₂SO₄

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 25 to 29. Fill in the appropriate word in question 27

Environmental Concerns

Earth is the only place we know of in the universe that can support human life. (25) _____, human activities are making the planet less suitable to live on. As the western world carries on consuming two-thirds of the world’s resources while half of the world’s population do so just to stay alive, we are rapidly destroying the (26) ______ resources we have by which all people can survive and prosper. Everywhere fertile soil is (27) ______ built on or washed into the sea. Renewable resources are exploited so much that they will never be able to recover completely. We discharge pollutants into the atmosphere without any thought of the consequences. As a (28) ______, the planet’s ability to support people is being reduced at the very time when rising human numbers and consumption are making increasingly heavy demands on it.

The Earth’s natural resources are there for us to use. We need food, water, air, energy, medicines, heat, shelter and minerals to (29) _______ us fed, comfortable, healthy and active. If we are sensible in how we use  the resources, they will remain indefinitely. But if we use them wastefully and excessively, they will soon run out and everyone will suffer.

A. neither

B. sooner

C. rather

D. either

1/ tế bào

2/ cơ thể

3/ sự thở

4/ phổi