Participles at work: instead of a clause

Replacing a kiu clause

Drop kiu and the verb, and put the participle where the verb was:

• La knabo leganta la libron estas mia amiko. - The boy reading the book is my friend.
• La veninta homo parolis. - The person who had come spoke.

A participle with nothing after it usually goes in front of the noun, like any adjective: la homo, kiu venis becomes la veninta homo.

One condition: the noun must be the subject of the clause you replace. In la libro, kiun mi legas, the book is not doing the reading, so an active participle cannot replace it. That needs the passive participles, -ata, -ita, -ota: see the passive.

The -e form, and its trap

The -e participle folds a whole time or reason clause into one word:

• Kiam mi finis la laboron, mi dormis. becomes Fininte la laboron, mi dormis. - Having finished the work, I slept.
• Ĉar li vidis min, li haltis. becomes Vidinte min, li haltis. - Having seen me, he stopped.

An -e participle has no subject of its own: it borrows the subject of the main clause. So this sentence says the house came home:

• Veninte hejmen, la domo estis malplena. - Having come home, the house was empty.

Check that whoever does the -e action is the subject of the main verb. If not, write the kiam clause out:

• Kiam mi venis hejmen, la domo estis malplena. - When I came home, the house was empty.

Go easy on esti + participle

Esti plus a participle builds a compound tense for every shade of time: mi estas leganta (I am in the middle of reading), mi estis leginta (I had read). They are correct, and mostly unnecessary:

Use the simple tense by default, and the compound only when being in the middle of it is the point. Compound tenses has the full set.