Marsha is an eager beaver and works like a mule1.
I already explained that beavers are industrious, but even beavers can’t hold a candle to the mule. The mule is big, strong, and completely single-minded in his work. Mules cannot have baby mules, so their only purpose in life is to work, work, and work some more.
 Marsha was soon appointed manager of the marketing department, in charge of 38 people all told. Quite a few old-timers2 couldn’t make head or tail of how such a newcomer could win the favor of the general manager and climb up the ladder so fast, getting the upper hand of all of them. In private, some even went so far as to fling mud at3 her, saying she tried to ingratiate herself with4 the general manager using her feminine charms. Anyhow, she never took their loose talk to heart and let people circulate whatever rumors they pleased.
 Young as she was, she knew the way around, hitting it off with not only the general manager but also rank-and-filers（普通成员, 一般人员）in the company. But she didn’t flatter herself and get on her high horse5，never even making it hot for those who had gossiped about her. When a problem appeared, she just talked with the individuals concerned with an open heart. When faced with an embarrassing situation, she always let the person down gently6（委婉待人；给人留面子；）. She was even-tempered（镇定的, 冷静的）and fair with everyone. Thus, she won respect from all around her and everything went swimmingly.
 Now everyone knew she had risen through the ranks6 because of her talent and keeping her nose to the grindstone7. When errors cropped up, she kept her cool and never passed the buck to8 others. She worked her way into9 great success. Of course, the praise spread all over: Marsha is an eager beaver and works like a mule.
 玛莎很快被任命为市场部经理，负责管理38个人。一些老资格的人搞不明白为什么这个新手赢得了经理的宠信，而且爬得这么快，占尽了风头。 私下里，有些人竟然恶意中伤，说她试图施展女性魅力来讨好总经理。然而，她从来就不把这些闲言碎语放在心上，任凭人们怎么高兴就怎么造谣。
 现在，大家都知道，她之所以能平步青云，是她才华出众，工作刻苦认真。出现差错了， 她就冷静下来，从来不推委责任。她工作兢兢业业，因而取得了成功。当然到处都能听到对她的赞美之词：玛莎做事很给力，踏实肯干不惜力。
work like a mule to work extraordinarily hard 工作非常卖力气
The doctor worked like a mule to help the dying patient pull through. Her life was saved because his herbal medicine worked like a charm.
old-timer [口]老资格的人, 老前辈, 旧式的人
The old-timers take objection to modern music, such as rap, rock’n’roll, and heavy metal.
fling mud at sb. 诽谤；中伤
This accusation against Mary was trumped up (捏造) by some dirty guys who racked their brains to fling mud at her.
ingratiate oneself with sb./into sb.'s favor 讨好某人；巴结某人；逢迎
He did his best to ingratiate himself with his employer.
let the person down gently 委婉待人；给人留面子。
I won't break the bad news all at once. I'll let her down gently. 我不会一下子把坏消息一古脑地倒出去，我会婉转地告诉她。
get on (one's) high horse to be or become disdainful, superior, or conceited 趾高气扬；目空一切；盛气凌人
Tom has a swelled head and likes to get on his high horse, treating others like dirt.
rise through the ranks to attain an increasingly high position 出类拔萃
The girl is just 17, but she has risen through the ranks of her classmates and is clearly one of our school’s top pupils.
put (one's) nose to the grindstone to work in earnest 认真地工作
Our employees are all loyal to our boss and put their nose to the grindstone from dawn till dusk, fulfilling their tasks superbly.
pass the buck to shift responsibility or blame to another 推御责任；把责任或责备推给别人
They lack teamwork and are apt to pass the buck once anything goes wrong.
work one's way into 兢兢业业地达成
The newcomer is down to the earth at work, and worked her way into a good position.