bài 2: change the active sentences into passive sentences of past simple
1> John earned money last year
->..........
2> Anna opened the window that room
->.........
3> We did our homework yesterday
->...........
4> I asked him some questions
->...............
5> He cut out the picture
->...........................
6> The sheep ate a lot of grass
->........................
7> We did not clean our rooms
->.......................
8> William did not repair the car
->....................
9> Did Sue draw this circle?
->.....................
10> Did you feed the dog?
->.....................
Bài 4: Cho ΔABC vuông tại A, đường cao AH. Gọi DE lần là hình chiếu vuông góc của H trên AB, AC. Chứng minh:
a> \(\dfrac{AB^2}{AC}\) = \(\dfrac{HB}{HC}\)
b> \(\dfrac{AB^3}{AC^3}\) = \(\dfrac{BD}{EC}\)
C> DE\(^3\) = BD . CE . DC