Read between the lines ( তাৎপর্য বোঝা ) Try to read between the lines of the letter.
A rainy day ( দুর্দিন ) Everybody should save something for rainy day.
A blessing in disguise ( বিপরীতে হিত ; প্রথমে খারাপ হিসেবে মনে হলেও পরবর্তীতে ভালো হয় ) Sam's motorcycle accident was a blessing in disguise because he got enough insurance money.
keep your chin up ( সুখি হওয়া ) His attempt keep your chin up
At a stretch ( একটানা ) He can run ten miles at a stretch.