21. What (happen) _____________ if everybody (use) _____________ flying cars. 22. My son (speak) ______________ English fluently if he (study) ____________ abroad. 23. If we (stop) _____________ cutting down so many trees, we (save) _____________ our planet. 24. If you (want) ___________, we (do) ______________ everything for you. 25. If they (leave) ____________ home now, they (catch) _________________ the bus. 26. If my parents (support) _____________ me, I (become) ___________ a better person. 27. If it (rain) _____________, I (get) ____________ wet. 28. Sally and Elizabeth (go) ____________ out tonight if their parents (allow) ____________ them. 29. They (visit) ___________ Eiffel Tower if they (travel) __________ to France. 30. If I (enter) ___________ university this year, my parents (give) _____________ me a computer. 31. If I (not/pass) _______________ the exam, my parents (be) ______________ very disappointed. 32. This TV is too old. If it (not/work) ______________, we (buy) ____________ a new one. 33. If the baby (not/eat) _______________, we (send) ______________ for the doctor. 34. If these shoes (fit) ________________ me, I (buy) _______________ them. 35. If he (not / stop) _________________ smoking, he (have) _________________ health problems. 36. If we (plant) ________________ more trees, we (have) _______________ more oxygen to breathe. 37. If you (write) _________________ the test carelessly, you (get) ________________ bad marks. 38. If she (take) _________________ a map, she (not lose) ________________ the way. 39. If you (get) ___________ enough sleep, you (feel) _____________ healthier. 40. People (make) ____________ the air more polluted if they (use) ______________ more cars. 41. If you (not/be) _______________ careful, you (fall) _______________. 42. If she (eat) _______________ that mayonnaise, she (be) ________________ sick. 43. If they (not/behave) ______________ well, their parents (punish) ________________ them. 44. You (miss) ______________ the flight if you (not go) ______________ to the airport early. 45. If more people (cycle) ________________, there (be) _____________ less air pollution. 46. If the weather (be) _____________ too hot, I (turn on) _______________ the air conditioning. 47. You (understand) ___________ conditional sentences if you (practice) ____________ them carefully. 48. We (arrive) __________________ there before noon if we (start) ______________ at 6 o’clock. 49. If we (practice) ___________ English more regularly, our English (be) __________________ better. 50. If we (borrow) _______________ books from the library instead of buying, we (save) _____________ our money. MÌNH ĐANG CẦN RẤT GẤP Ạ !