Cho đường tròn (O) và điểm M nằm ngoài đường tròn. Qua M kẻ các tiếp tuyến MA, MB tới đường tròn(O) với A,B là các tiếp điểm.

a) Cm 4 điểm A,B,M,O cùng thuộc 1 đường tròn

b) Kẻ đường kính AC của đường tròn (O). Cm: OM//CB

c) Vẽ BK vuống góc với AC tại K. Chứng minh CK.OM=OB.CB

d) Tiếp tuyến tại C của đường tròn(O) cắt AB tại D. Cm OD vuống góc với CM

I am not free tomorrow, so i can't help you tidy our room

=>If

Complete the sentences

1. Many house/ destroy/ fire/ recently

2. The victims/ provide/ food/ clothing/ since yesterday

3. Food/ blankets/ give out/ homeless people/ volunteers/ so far

4. My parents/ visit/ Europe/ this time next week

5. At 8 o'clock thí evening my friends and i/ watch/ famous film/ the cinema

6. Daisy/ sit/ the plane/ 9 am tomorrow .

7. She/ play/ chess/ her son/ 7 o'clock tonight.

8. He/ work/ this moment tomorrow morning.

9. They/ make/ their presentation/ this time tomorrow morning.

10. I/ watch/ a since fiction film/ TV/ 9.00 tonight.

11. The polluted water/ cause/ the death/ the fish

I. Conditionnal sentence type 2

1. There are so many billboards in our city. People can not enjoy the view.

If..............................................................

2. There is so much light in the city at night. We can not see the stars clearly.

If...............................................................

3. We turn on the heater all the time. We have to pay three million dong for electricity a month.

If...............................................................

4. She has a headache after work every day. She works in a noisy office.

If.................................................................

5. We won't hold the festival. It costs too much money.

If..................................................................