It

Pronoun

  would

Auxiliary

  have

Auxiliary

  been

Auxiliary

  visible

Adjective

  to

Adposition

  me

Pronoun

,  had

Auxiliary

  I

Pronoun

  only

Adverb

  looked up

  as

Subordinating conjunction

  it

Pronoun

  passed

Verb

.

It would have been visible to me, had I only looked up as it passed.

It would have been visible to me, had I only looked up as it passed.