If you (send) (1) this letter now, she (receive) (2) it tomorrow.
If I (do) (3) this test, I (improve) (4) my English.
If I (find) (5) your ring, I (give) (6) it back to you.
Peggy (go) (7) shopping if she (have) (8) time in the afternoon.
Simon (go) (9) to London next week if he (get) (10) a cheap flight.
If her boyfriend (phone/not) (11) today, she (leave) (12) him.
If they (study/not) (13) harder, they (pass/not) (14) the exam.
If it (rain) (15) tomorrow, I (have to/not) (16) water the plants.
You (be able/not) (17) to sleep if you (watch) (18) this scary film.
Susan (can/ move/not) (19) into the new house if it (be/not) (20) ready on time.