彼はうそをついているのだという考えが頭に浮かんだ。の英語

The idea occurred to me that he was lying.

An idea flashed through his mind.

He tends to consider things too much earnestly.

A good idea came to him.

A good idea occurred to him.

A crazy idea took hold of him

A good idea occurred to him.

A good idea came to him.

He thought of a brilliant idea.

He is reticent but has solid ideas.

An evil thought came into his head.

Don't put such silly thoughts into his head.

He pondered deeply with knitted brows.

I sensed what he was thinking.

The idea struck him as a silly one [as silly].

He must be crazy to do such a thing.

An idea came to him.

He apparently has some ulterior motive.

An idea formed in his mind.

He takes things too seriously.

He is insisting both of those are his own.

Fancy him [his] telling a lie!

It occurred to him that he should start at once.

It is absurd trying to persuade him.

He was lost in reverie [thought].

He is possessed with a curious notion―obsessed by a strange notion.

It's shameful that he behaves that way.

A terrible idea suddenly struck him.

He is frugal, to say the least of it.

His nonsensical behavior is shocking.