expression (n) 表达
He’s expression is weard.
Distinguish {he’s} and {his}.
And watch your spelling.
His expression is weird.

He’s expression is clear.
Distinguish {he’s} and {his}.
His expression is clear.

Theirs expression is bad.
Distinguish {their} and {theirs}.
And {expression} is a countable noun.
Their expressions are bad.

quivering(v)抖动
He quivering.
Don’t miss Be verb in present continuous tense.
He is quivering.

I was quivering.
OK!

He is quivering whe he is cold.
Watch your spelling!
He is quivering when he is cold.