Relative pronouns are widely used in English, but they are difficult for language learners. Here is an app with detailed grammatical notes on relative pronouns and clauses, two practice activities with 50 items each, and 2 quizzes with 50 items each.
The practice activities give you the opportunity to practice using basic relative pronouns. The quiz activities test your ability to make advanced use of relative pronouns.
This App is designed for English language learners (ELL students) regardless of their levels of English language proficiency.
Even though its primary focus is for ESL/EFL, native English speakers too may find it interesting.
TESL/TEFL teachers, whose comments are welcome, may want to recommend it to their students.