cứu tui phần này với

21. B thay thế, thay phiên

22. D It uses enzymes to break down water.

Dẫn chứng :

+) His invention uses a molybdenum compound to break down water into hydrogen and oxygen.

+) Unlike other methods, no electricity is required and the reaction happens at atmospheric temperature.

23. B - The use of molybdenum is the perfect choice because, although rare, it is cheap and found all around the planet.

24.B save environment

→ Dẫn chứng : If this technology were to become widely available, it would prove disastrous for petrol station owners and would also save the planet from the impending environmental catastrophes. ( Câu cuối của bài )

25. B -> had watched

26. D -> the most

27. These flowers should be watered every day

28. My brother, who is a doctor, participated in the fight against the epidemic