不择手段by any kind of means by hook or crook play hard by fair means or foul

不知所措be at a loss be all adrift lose one’s head out of one’s wits 

才疏学浅have little talent and learning

惨绝人寰extremely cruel

沧海桑田time brings a great change to the worlds

沧海一粟/九牛一毛a drop in the bucket  来源：考试大

草木皆兵a state of extreme nervousness

层出不穷emerge in endlessly

层峦迭嶂peaks over peaks

察言观色carefully watch what sb. is doing and saying

姹紫嫣红very beautiful flowers

畅行无阻checkless

车水马龙heavy traffic

沉默寡言taciturnity  来源：考试大

称心如意well-content

趁热打铁strike while iron is hot Hold a wolf the iron is hot

成群结队gang horde 来源：考试大

诚惶诚恐with reverence and awe

诚心诚意sincere desire 

承上启下a connecting link between the preceding and the following

吃苦耐劳tough

吃里扒外live on sb. while helping others secretly

痴心妄想、胡思乱想wishful thinking 

持之以恒preserve

叱咤风云ride the whirlwind

愁眉苦脸pull a long face snoot 

愁眉苦脸的，愁眉苦脸地woebegone 、morosely

臭名远扬，臭名昭著flagrancy， notorious

出乎意料unexpected

出口成章have an outstanding eloquence

出类拔萃，鹤立鸡群fill the bill supereminence 

出谋划策give counsel suggest

出奇制胜defeat sb. by a surprise action

出生入死go through fire and water