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。