Active participles: an introduction

A Russian participle is an adjective made from a verb. English has the idea too ("the reading student", "a man who has read the report"), but where English mostly reaches for a relative clause, written Russian can pack the whole clause into one word that agrees with its noun like any adjective.

The quickest way to build a present participle is from the 3rd person plural: drop the final -т and add -щий. читают gives читающий, говорят gives говорящий, пишут gives пишущий. That is why the vowel follows the conjugation: a 2nd-conjugation verb gives -ащ-/-ящ-, never -ущ-/-ющ-. For the past, take the past-tense stem: прочита-л gives прочитавший; a stem ending in a consonant takes plain -ш- (нёс gives нёсший).

Participles decline like ordinary adjectives, so the ending tracks the noun's case, gender and number: Я дал слово студенту, читающему доклад ("I gave the floor to the student who is reading the paper"). English "reading" has a single form, which is why English speakers tend to leave the participle in the nominative.

Where you will meet them: news, Wikipedia, signs and official notices, such as Пассажиры, прибывающие в Шереметьево... on an airport screen. In conversation Russians use the который clause instead: студент, который читает доклад. At B1 the goal is to recognise participles in what you read and to turn them into который clauses and back.