Выберите правильную форму причастия и переведите предложения на русский язык:
1. (Being written, having written) this exercise, I doubted if it was correct.
2. Take care when (having been crossed, crossing) the street.
3. The door (bolted, bolting) on the inside could not be opened.
4. (Having been written, having written) by him before he began to study it seriously, the article was rather primitive.
5. The letter (receiving, received) yesterday was most welcome.