1. I put my trust in you.
我信任你。
还能这样说：
I trust you.
I have faith in you.
谚语：
Put your shoulder to the wheel.
鼎力相助。
2. I rather doubt that.
我非常怀疑。
还能这样说：
It sounds fishy to me.
I am doubtful about that.
应用解析：
beyond doubt 毫无疑问；
cast doubt on 对……产生怀疑；
lay sb.'s doubts 消除某人的疑虑
3. What a pity!
真遗憾！
还能这样说：
What a shame!
Too bad!
应用解析：
feel pity for sb. 同情某人；
have pity on sb. 可怜某人；
in pity (of) 怜悯……；同情；
out of pity 出于怜悯
4.I know that's what I must do.
我知道那是我必须做的。
还能这样说：
I know it is my obligation.
I should shirk my duty to do that.
应用解析：
msut作情态动词讲，表示必要、命令或强制（必须，得）；表示肯定的推测（一定是，谅必，八成）；

表示不可避免性（必然要，必定会）；表示主张（一定要，坚持要）。
5. No smoking!
请勿吸烟！
还能这样说：
You are not permitted to smoke here.
Smoking is not permitted here.
谚语：
There is no smoke without fire.
无火不起烟；无风不起浪。
6. You had better hurry up.
你最好快点。
还能这样说：
You must be fast.
You'd better be as soon as possible.
应用解析：
no hurry 不忙，不必着急，有充裕的时间；
split of a hurry 极为匆忙；
without hurry or bustle 不慌不忙地；
hurry on (with) 赶紧办理；急急忙忙地做
7. I regret having done that.
我后悔那样做。
还能这样说：
I shouldn't have done this.
I felt sorry for what I have done.
谚语：
A moment's error can bring a lifelong regret.
一失足成千古恨。
8. That is boring!
真讨厌！
还能这样说：
Darn it.
It is disgusting.
应用解析：
表示厌恶的同义词还有：dull，tedious，tiresome，wearisome。
例如：It's tiresome to keep doing this.
一直这样做真烦人。