英文修改: 感谢前线医务人员信
Source: 百度翻译互助吧
(prepared by: alexcwlin; edited by: Adam Lam)

(a)   suggested version
(b)   original version

Letter #1:

(a)   Dear Medical Workers: (note: capitalize “Worker” as a Proper Noun)
(b)   Dear Medical workers:

(a)   (no change)
(b)   I am Hua Li, a senior high school student in Shanxi.

(a)   I'm writing to express my sincere gratitude to you all for your devotion and sacrifice in this battle against the novel (Note: “novel” is general term and should not be capitalized as “Novel”) Corona Virus.
(b)   I'm writing to express sincere gratitude to you all for your devotion and sacrifice in this battle against the Novel Corona Virus.

(a)   In this epidemic crisis, it is you who, despite a dearth in resources (Note: Many things are short, not just equipment) and health risks, work diligently to rescue those infected patients who are striving for their lives.
(b)   In this epidemic, it is you who, despite the lack of equipment and the potential of infection, desperately rescue those infected but striving for life.

(a)   It is also you who have found out more about the virus in an effort to defeat it.
(b)   It is also you who have shed new light on the virus with expertise to build up our confidence to defeat it.

(a)   (no change)
(b)   It is you who deserve all the admiration and love!

(a)   I can never thank you enough for your selfless and noble contributions.
(b)   I can never express our thankfulness too much for your selfless contribution.

(a)   I’m confident that our joint efforts in China will win out in the end.
(b)   It's widely believed that our joint efforts China will win the battle and make a quick recovery.

(a)   Good luck and take care.
(b)   Good luck and stay well!

(a)   (Note: Earlier you use “Li Hua” and here you use “Hua Li”. Make up your mind and use one format for both).
(b)   Yours sincerely,
        Li Hua

Letter #2:

(a)   Dear Healthcare Workers: (Note: Capitalize the names for Proper Nouns)
(b)   Dear healthcare workers,

(a)   (no change)
(b)   I am Hua Li, a senior high school student in Shanxi.

(a)   On behalf of all the students and teachers in our school, I am writing to express my appreciation to all of you healthcare workers who are fighting the COVID-19 epidemic at the frontline. (Note: COVID-19 is not defeated yet).
(b)   On behalf of all the students and teachers in our school, I am writing to express my appreciation to you, all the healthcare workers who defeat the COVID-19 epidemic in the frontline.

(a)   In the process, you work endless hours to treat patients despite a lack of equipment and other resources.
(b)   In order to wipe out the novel coronavirus as soon as possible, you try your best to treat patients despite the lack of medical prevention equipment.

(a)   In the meanwhile, you have also made plenty of headway in finding a cure for the disease
(b)   In the meanwhile, you also make many clinical trails so as to confirm the best therapy methods.

(a)   We believe that through joint efforts of everyone involved, we will win the battle against the COVID-19 in the near future.
(b)   We believe that through joint efforts from medicine and other industries, we will win the battle against the COVID-19 in the near future.

(a)   (no change)
(b)   Thank you again for your devotion and sacrifice!

(a)   Good luck and stay well!
(b)   Good luck and stay well!

(a)   (no change)
(b)   Yours sincerely,
        Hua Li

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Both letters are well-written.

I personally like Letter #1.

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