Chuyển câu sao cho nghĩa không đổi: Earthquakes have become more frequent recently. (Increased)

1. Earthquakes have become more frequent recently. INCREASED
The ........................................................................ recently.
2. I’m not sure whether the new system is efficient. OF
I’m not sure about ................................................... the new system.
3. They were still discussing the project when I asked him. UNDER
The project was still ................................................... when I asked him.