IF / UNLESS / ALTHOUGH / BECAUSE / SO / BUT / AND / HOWEVER / THEREFORE

15. ……………………. the weather was rainy and cold, we stayed at home.                              16. ……………………. he was appointed to a higher promotion, he decided to quit his job 17. ……………………. my wife had left the car keys, I could have picked her up at the station                                                                                                                                       18. He’ll be late for the train ……………………. he doesn’t start at once                                     19. ……………………. she was very tired, she helped her brother with his homework.                  20. …………….… you agree, nothing can be arranged                                                 21. We can't go to Julia's party ……………………. we're going away that weekend.                        22. John came to the party ………….………. he hadn’t been invited                                        23. The boy can’t reach the shelf ……………………. he’s not tall enough                      

24. I was very tired, ……………………. I determined to walk on to the next village.                      25. Mai worked hard, ……………………. she passed her exam.                                       26. The professor told me that I was doing well, ……………………. my final grade was awful!                                                                                                                                        27. He used to smoke a lot, ……………………. now he doesn’t smoke any more.

28. I studied Spanish for four years in high school. ……………………., I had trouble talking with people when I was traveling in Spain.                                                                                    29. The windows were all left open. ……………………., the room was a real mess after the windstorm.                                                                                                                               30. He is one of the best students of the school. …………………., he can’t pass the national chemistry exam

Fill the blank in the sentences with a suitable word or a phrase                                                     1. The train arrived …………….. the station 20 minutes late.                                                      2. The new store was crowded ………………. shoppers                                                                3. Are you content …….…..… your present job, Mr. Smith?                                                         4. They tried to put the fire …….………….…but they couldn’t                                                  5. They are ………… danger of losing everything.                                                          6. What time does the baby usually wake ……………...?                                                       7. She is always interested ……………... Literature, which is her favourite subject                       8. …………….. my panic and fear, I could not remember where the dock was.                          9. I put …………….. the tent and cooked a meal                                                                       10. From the time my alarm clock goes ………….….., I am beginning my workout.                     11. We're leaving at eight o'clock, so you've got half an hour to …………… ready                 12. After working hard for two hours, they stopped to ……………... a rest                         13. Mr. Vy pumps water into his plot of land while his wife ……………... the transplanting            14. I …………….. death in the face when the plane began to shake and seemed to dip

Tổng số hạt electron, proton và nơtron trong một nguyên tử X là 42. Trong đó số hạt

mang điện gấp đôi số hạt không mang điện.

a. Hãy viết kí hiệu nguyên tử của X.

b.  Nguyên tử Y là đồng vị của nguyên tử X. Tổng số hạt của nguyênt ử Y nhiều hơn của nguyên tử X là 2 hạt. Hãy tìm số nơtron và viết kíhiệu nguyên tử của Y.