Bài  5: Tìm 2 số nguyên tố x,y sao cho:

         1,x² – 2y² = 1

         2, x² – 6y² = 1

         3, x² + 117 = y²

         4, x² + 165 = y²

III. Complete the sentences by filling in the gap with must and a verb

1. All visitors ………..to reception. You ………….and stay with us one week

2. Candidates …………..…….two questions from each paper

3. I ……….to the bank and get some money. I …….….you look absolutely great

4. We …………..together soon for lunch. We …….……for lunch soon.

5. I …………., I wasn’t looking forward to it. I ….…….some ironing tonight.

6. You ………….…. hungry after all that walking.

IX. Find ONE mistake in each of the following sentences and correct it

1. He is intelligenter than I am……………………

2. She is tallest girl in the village……………………

3. Is there a lot of food in the fridge? _ No, there isn’t some.………………

4. We must not forgets your birthday.……………………

5. My house is beautiful than hers.……………………

6. Where can I find Mr. Brown? _ He is at the sixth floor. ……..…………

7. Thank you very much. Where is the lift? ____ He’s over there.……………

8. Do you like your place new? _ Yes, we do. It’s a big house.………………