48. My brother whose house was broken in called the police.

49. Mary was too very tired to study more.

50.If Emily wasn't sick today, she could go to school.

51.Although my grandparents are very busy, they spend a lot of time taking care of us.

52. The floor hasn't been cleaned yet.

53.We haven't seen our grandfather for five month.

54. I wish I could remember the answers to these questions.

55. I spent three hours cleaning the house yesterday. 

P8. 48.My brother whose house was broken in called the police.

49. Mary was too tired to study.

50. If Emily wasn't sick today, she could go to school.

51. Although my grandparents are very busy, they spend a lot of time taking care of us.

P9. 52. The floor hasn't been cleaned yet.

53.We haven't seen our grandfaather for five months.

54. I wish I could remember the answer to these questions.

55. I spent three hours cleaning the house yesterday.

BTKL: \(a=\Sigma m_{O_2}=m_{hh\text{ oxit}}-m_{hh\text { KL}}=14,2-7,8=6,4(g)\)

1 If I were you I would recycle these plastic carrier bags

2 The pilots suddenly struck, so all flights had to be cancelled

3 The polluted environment causes the death of birds and plants

4 The contaminated food leads to people's poor health

chữ đẹp quá :))

\(m_{HCl\left(1\right)}=600.2,5\%=15g\\ m_{HCl\left(2\right)}=400.15\%=60g\\ C\%_{HCl.sau}=\dfrac{75}{1000}\cdot100\%=7,5\%\)