To crown the effect - to give additional perfect effect
Crown of thorns - something that causes pain and suffering
Crowning glory - someone's greatest achievement
To crown it all - used for all about the last and worst thing
One-size-fits-all - suitable for all circumstances
Once in a blue moon - rarely
One man army - a well trained and heavily armed
Once bitten twice shy - an unpleasant experience induces caution
One up on - having an advantage over
To one's heart's content - to the fullest level of satisfaction
In a jiffy - in a very short time
Piece together - create something by joining the seperate parts of it together
Time and again - repeatedly
Frantic speed - very quickly
be completely stumped - confused, not to know what to say
Be broken - give up hope
Feel out of place - feel uncomfortable
Speak at length - review in detail
Feel at home - feel comfortable
Sea of knowledge - lots of knowledge
Broaden one's horizon - expand one's interest/knowledge
To hit the bull's eye - to get something exactly right
He worked hard and hit the bull's eye in the exam.
To be taken by surprise - to encounter someone who is not prepared
Enemy was taken by surprise with the advent of Indian army.
To get a toehold - to obtain an initial, stable position
Under the cover of - being kept secret
Thieves moved under the cover of darkness
A spell of - a short period
One's second innings - another part
Touch the hearts - make feel better
Keep one going - give enough energy
In pursuit of - in order to achieve something
To smell a rat - to feel something foul
To be keen - to be interested
On the trail of - searching someone
To feel under the weather - to feel sick, ill