1. I was making phone calls all evening

2. I was waiting for half an hour

3 .I was making sandwiches all afternoon

4. I was sitting for 2 hours

5.My neighbour was playing loud music all night

mà y=1⇒x>y⇒x=2,y=1

\(\dfrac{1}{x}-\dfrac{1}{y}=\dfrac{1}{2}\Leftrightarrow\dfrac{x-y}{xy}=\dfrac{1}{2}\)

do x,y nguyên nên:\(\left\{{}\begin{matrix}x-1=1\\x.y=2\end{matrix}\right.\)

ta có :2=1.2

mã-y=1⇒x>y⇒x=2,y=1

Tham khảo:

1. San hết gạo trong bao lên 2 đĩa cân, mỗi đĩa có 5kg gạo

2. Đặt hết số gạo ở đĩa trái xuống.

Đặt quả cân 4kg lên.

San bớt gạo ở đĩa phải, số gạo san bớt chính bằng 1kg

\(0,6x-\dfrac{1}{3}x=\dfrac{4}{9}\)

\(\Leftrightarrow x\left(\dfrac{3}{5}-\dfrac{1}{3}\right)=\dfrac{4}{9}\)

\(\Leftrightarrow x.\dfrac{4}{15}=\dfrac{4}{9}\Rightarrow x=\dfrac{4}{9}:\dfrac{4}{15}=\dfrac{5}{3}\)

\(A=\left(\dfrac{1}{2}-1\right)\left(\dfrac{1}{3}-1\right).....\left(\dfrac{1}{2021}-1\right)\)

\(=\dfrac{-1}{2}.\dfrac{-2}{3}.....\dfrac{-2020}{2021}\)

\(=1.\dfrac{1}{2021}=\dfrac{1}{2021}\)

Nhiệt độ đông đặc của rượu là -117^oC,

They have a lot of...activities.... in the summer.          (ACT).

a)50^oC=(50.1,8)+32=122^oF

b)113^oF=(113-32):1,8=45^oC

1. without

2. for

3. at - on

4. about - from

5. to - on

6. of

7. against