giải hệ phương trình

x - y = m

2x + y = 4

Quần thể người giống và khác quần thể sinh vật khác ở những điểm nào? Tại sao lại có sự khác biệt giữa quần thể người với quần thể sinh vật khác?     

Chỉ ra biện pháp tu từ và nêu tác dụng của biện pháp tu từ:

Sông được lúc dềnh dàng

Chim bắt đầu vội vã

Có đám mây mùa hạ

Vắt nửa mình sang thu.

5. He doesn’t have time. He doesn’t read this novel.
If______________________________.
6. Because she misses the bus, she is late.
If______________________________.
7. Peter doesn't study hard, so he can't get good marks.
If______________________________.
8. My sister is absent from her class because she has a terrible headache.
If______________________________.
9. Windy doesn’t come, so we cancel the meeting.
If______________________________.
10. He is angry, so he doesn’t say anything.
If______________________________.

1. I'll buy a new hat. I'll give it to you.
If______________________________.
2. Today isn't Sunnday. The pupils can't go swimming.
If______________________________.
3. He isn't here. He doesn’t have a lot of fun.
If______________________________.
4. My brother will have enough money. He will buy a bicycle.
If______________________________.
5. He doesn’t have time. He doesn’t read this novel.
If______________________________.
6. Because she misses the bus, she is late.
If______________________________.
7. Peter doesn't study hard, so he can't get good marks.
If______________________________.
8. My sister is absent from her class because she has a terrible headache.
If______________________________.
9. Windy doesn’t come, so we cancel the meeting.
If______________________________.
10. He is angry, so he doesn’t say anything.
If______________________________.

1.If it costs too much, I (buy) ……………………….a small one.
2.If you (drive) ………………………….more carefully, you wouldn’t have so many accidents.
3.What (happen) ………………………………..if there (not be) gravity?
4.If I (make) ………………………..that mistake again, my teacher (get) ……………… angry with me.
5.If I spoke English, my job (be) ………………………..a lot easier.
6.If he (go) ………………………to London, he will meet his old friend.
7.Would you mind if you suddenly (win) …………half a million pounds?
8.I (lend) …………..them some money if they (ask) ………….me.
9.If we (know) ……………………who he is, we (invite) ………………him to speak at our meeting.
10.If they invite us, naturally we (go) ……………….to the party.
11.If Don and I (have) ……….enough money, we would buy a house.
12.Ice (turn) …………………..to water if you (heat) …………………it.
13.I (speak) ……………….to France if I see him.
14.If I realize that the traffic lights are red, I (stop) ………….
15.They (not / let) ……………………….you in if you come late.
16.If you (not / go) ……………………away, I’ll send for a policeman.
17.If I (be) ……….in your place, I (accept) ………….Mr Long’s officer.
18.If I (win) …………………a big prize in a lottery, I’d give up my job.
19.If Tom is here, he (be) …………………able to advise us.
20.I am busy. If I have free time, I (go)…………..