1. Fill in the blank with because or because of : 1. It was difficult to deliver the letter …………the sender had written the wrong address on the envelope . 2. Nancy Lee was awarded a scholarship ……… her superior scholastic ability. 3.We had to drive around the baby …….the bridge was destroyed in the storm. 4. ……….the invention of computers , pupils no longer spend much time on calculating. 5. I catch cold now …………….going out in the rain yesterday. 6. We plan to spend our vacation in the mountains ………….the air is purer there. 7. We decided the leave early ……………..the party was boring. 8. The students arrived late ……………….the traffic jam 9. Rescue attempts were temporarily halted ……………..the bad weather . 10. Paul may not go to the football game ….. his grades. 11. The teacher is sick ……………..her injured leg. 12. Mary looks happy ……………….she has just got good marks. 13. I couldn’t read the letter ……………….it got dark 14. I didn’t come in time ………..the traffic 15. He stayed at home yesterday ……………….the heavy rain.