He is totally a stick-in-the-mud.
他是个名副其实的老古董。
a stick-in-the-mud字面意思是：“插在烂泥中的树枝”，树枝在烂泥中没有任何松动的余地，以此来比喻：“刻板单调、墨守成规的老古板”。因此，当美国人说"He is totally a stick-in-the-mud."时，他/她要表达的意思就是:"He is really an old-fashioned fossil."、"He is very dull and conservative."、"He is an old fuddy-duddy."。
情景对白：
Terry: Our boss is always afraid of trying new things.
泰瑞：老板总是害怕尝试新事物。
Benjamin: Exactly! He is totally a stick-in-the-mud.
本杰明：的确如此！他是个名副其实的老古董。
搭配句积累：
①What do you think of our new boss?
你觉得我们的新老板怎么样啊？
②Our new colleague looks very firm and severe.
新来的同事看起来又古板又严厉。
③That old man still insists women stay home instead of working outside.
这个老头始终认为女人不该出去工作，就该在家相夫教子。
④Our boss never accepts new concepts or new ideas.
我们老板从不肯接受新理念和新思想。
单词：
1. fossil n. 化石，僵化的事物，顽固不化的人
I am living fossil of new age.
我简直就是新时代的活化石。
Fossil, as a result of non-renewable, scarcity and uniqueness, has high value of collection and economic value.
由于化石的不可再生性，稀缺性，唯一性使其具有了极高的收藏价值和经济价值。
2. conservative adj. 保守的
People tend to be more aggressive when they're young and more conservative as they get older.
人们年轻的时候往往较为激进，而随着年龄的增长会变得保守起来。
The girl was well dressed, as usual, though in a more conservative style.
这个女孩穿得一如往日那样讲究，只是风格比平日更为传统。
3. severe adj. 严厉的
This was a dreadful crime and a severe sentence is necessary.
这一罪行十分恶劣，必须要重判。
Before she could reply, my mother launched into a severe reprimand.
她还没来得及回答，我妈妈就开始严厉地训斥起她来。
