1. By the time, I decided to go on a diet, I had put on ten kilos.

2. They waxed the car after they had washed it.

3. Before Lisa sat on the sofa to watch TV, she had made a sandwich

4. As soon as we packed our suitcases, we left for the airport

5. When the lecture started, I entered the lecture hall

6. This is the first time I have tasted Chinese food

7. He has never read a science-fiction book before

8. Như câu 2

9. While Mark was parking his car, he noticed the wing-mirror was broken

10. Ad Judy was walking down the street, she saw an accident

11. I'm sorry I can't take to you now as I'm about to work

12. The Council intends to close the old swimming pool

13. They are planning to have a big wedding in the summer

14. The economy is on the point of collapsing

15. My grandfather is about to go far, far far far far far far far away : (

16. You are due to arrive at 7.30 in the evening

Câu 1: D

Câu 2: C

Câu 3: C

Câu 4: D

Câu 5: A

 1: D

 2: C

 3: C

 4: D

 5: A

xin lỗi, mình không giúp được, bạn tự làm đi nhé:)

mình đang thắc mắc là không có giám thị hay sao mà bạn chụp được hẳn cái đề thi như này cũng chịu

Trời ơi!

Câu 3: 

Sẽ thực hiện 3 vòng lặp

S=6

Chương trình:

uses crt;

var s,n:integer;

begin

clrscr;

s:=0;

n:=2;

while (s<5) do

s:=s+n;

writeln(s);

readln;

end.

Bài 4: 

b: Xét ΔAHB vuông tại H có HM là đường cao

nên \(AM\cdot AB=AH^2\left(1\right)\)

Xét ΔAHC vuông tại H có HN là đường cao

nên \(AN\cdot AC=AH^2\left(2\right)\)

Từ (1) và (2) suy ra \(AM\cdot AB=AN\cdot AC\)

\(TanB=\dfrac{AC}{AB}\Rightarrow Tan30^o=\dfrac{AC}{4,5}\Rightarrow AC=Tan30^o.4,5=\dfrac{3\sqrt{3}}{2}\left(m\right)\)

\(CosB=\dfrac{AB}{BC}\Rightarrow Cos30^o=\dfrac{4,5}{BC}\Rightarrow BC=Cos30^o.4,5=\dfrac{9\sqrt{3}}{4}\)

Chiều cao ban đầu của cây tre là: \(\dfrac{3\sqrt{3}}{2}+\dfrac{9\sqrt{3}}{4}=\dfrac{15\sqrt{3}}{4}\approx6,5\left(m\right)\)

Câu 4: 

Thay x=2 và y=-1 vào hệ, ta được:

\(\left\{{}\begin{matrix}2a-b=4\\2b+2=-2\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}b=-2\\a=1\end{matrix}\right.\)