Cái này giải sao vậy ?

50. They have raised awareness of conservation since 2003.

- Ta có cụm: raise awareness (nphr): nâng cao nhận thức

51. The World Wild Fund has worked hard for many years to protect endangered species.

52. Volunteers have gained useful experience in a broad range of fields.

- Ta có cụm: gain experience (v): tích luỹ kinh nghiệm

53. Our campaign has raised funds for the charity organization.

54. An anonymous businesswoman has donated one million dollars to the charity.

55. She has done voluntary work for the Red Cross for 10 years. 

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`@` Thì HTHT

(+) S + have / has + Vpp 

(-) S + have / has + not + Vpp

(?) Have / Has + S + Vpp?

- Lưu ý

`+` He / she / it / N số ít + has

`+` I / you / we / they / N số nhiều + have

`+` since + mốc thời gian

`+` for + khoảng thời gian