Chủ đề:
Bài 1: Căn bậc haiCâu hỏi:
a, 3x^2 - 4x + 1 < 0
b, 5x^2 + 12x - 17 ≥ 0
c, x^2 + 11x - 30 > 0
d, x^2 - 12x + 35 ≤ 0
The first electronic computer (26. build) ................... at the university of Pennsylvania in 1946. Although the computer looked like machines built in the 19th century. Computers were sold commercially for the first time in the 1950s, and a lot of progress (27. make) ................. sice then. Computers are now much smaller and more powerful, and they (28. can/ buy) .....................much more cheaply.
Computers (29. use) ............................. in many fields - in business, science, medicine and education, for exsmple/ They (30. can/use) ...................... to forecast the weather or control robots which make cars. The computer's memory is the place where information (31. keep) ...................... and calculations (32. do) .......................
16. We were shoked at the news of his ...................... [die]
17. David Copperfield is famous ...................... [magic]
18. I think gun toys are ............................ gifts for the children [suit]
19. The work was still at ..................... leavel [exoeriment]
20. My brother draws acrtoons for a ...........................magazine [humor]
Two friends were walking through the forest (1. when/ and/ after/ suddenly) a beer attacked them. One turned down and fied. He (2. climb/ climbing/ climbed/ to climb) up a tree and sat there while the (3. boy/ girl/ other/ student) remained on the road. There was not thing (4. of/ with/ about/ for) him to do but fall into the ground and play dead. The bear came up to (5. he/ him/ the tree/ his) and sniffed. The boy even stopped (6. breath/ breathe/ breathing/ to breathe). The bear sniffed his face, decided he was (7. die/ dead/ death/ died) and lumbered off. When the bear was (8. gone/ go/ to go/ going) the other boy climbed down and said with a smile. "What did the bear whisper in your ear?" " It said that someone (9. who/ which/ whom/ that) deserts his friends in time of danger (10. are/ will be/ must be) not a good friend at all"