Youth #Idioms
• in the flower of someone's youth: young and the most active period of life
• at your mother's knee: learned when young
• knee-high to a grasshopper [informal]/spring chicken: very small, young

Prepositions: Made & Compare #Grammar #Preposition
• Made of: composed of
• Made from: turn into another form
• Made out of: change from one thing to another
• Made with: ingredients of food & drink
• Made in [place]
• Made by [someone]
• Compare with: show difference between two things of the same type
• Compare to: show similarity between two different things

Notes:• When you are considering the use of made from, first think about their original existence, followed by states: gas, liquid, solid, and characteristics.
• Compare with usually show extreme differences.

invalid #Vocabulary
/ˈɪnvəlɪd/ noun: disabled/weak person
• He is invalid as he faced a tragic accident.

/ˈɪnvəlɪd/ verb: remove (someone) due to injury; disable by injury
• He was invalided out from the military because his leg was shot by a gun.
• He got invalided due to breaking his bones.

/ɪnˈvalɪd/ adjective: false
• Without providing any solid proof, your argument will be counted as invalid.

Word forms:
• invalidly (adverb): in the false way

Prepositions: Bad, Weak, Poor #Grammar #Preposition
• Bad/Worse/Worst at• Weak in/at• Poor at: below standard
• Poor in: lacking

Serious #Idioms
• beyond a joke: used to be funny but turned serious
• no laughing matter: serious
• take a joke: laugh when someone teased you and not be offended