1.This flower is watered (by my father) every morning.

2.Fiona was invented to John’s birthday party last month.

3.The dinner is being prepared (by her mother) in the kitchen.

4.Our teeth should be cleaned twice a day.

Ta có 

bca = abc x 2 + 81

100b + 10c + a = (100a + 10b + c) x 2 + 81

100b + 10c + a = 200a + 20b + 2c + 81

Cùng bớt 20b + 2c + a được :

80b + 8c = 199a + 81

8 x bc = 199a + 81

Vì 0 < a \(\le\) 9 suy ra a = 1

Khi đó 8 x bc = 280

=> bc = 35

Vậy abc = 135

1.This flower is watered (by my father) every morning.

2.Fiona was invented to John’s birthday party last month.

3.The dinner is being prepared (by her mother) in the kitchen.

4.Our teeth should be cleaned twice a day.

5.The English grammar has been explained (by our teacher).

1.This flower is watered (by my father) every morning.

2.Fiona was invented to John’s birthday party last month.

3.The dinner is being prepared (by her mother) in the kitchen.

4.Our teeth should be cleaned twice a day.

5.The English grammar has been explained (by our teacher).

6.The accident was caused in this city (by some drunk drivers).

Nguyễn Đình Dũng hôm qua nói không vào nữa mà hôm nay lại !

Ở một loài thực vật, màu sắc hoa do một gen có 2 alen (D,d) quy định; Hình dạng cây do hai cặp gen Aa và Bb cùng quy định. Cho F₁ tự thụ phấn thu được F₂ có tỉ lệ kiểu hình: 56,25% cây quả dẹt, vàng; 18,75% cây tròn, vàng; 18,75% cây tròn, xanh; 6,25%  cây dài, xanh. Kiểu gen của cây F₁ có thể là

A. A D a d Bb

B. AaBbDd

C. A d a D Bb

D. A B a b Dd