B={4}

A={ 21;22;23;24}

2010/2+2010/6+2010/12+...2010/9900

=2010/1x2+2010/2x3+.....+2010/99x100

=1-1/2+1/2-1/3+......+1/99-1/100

=1-1/100=99/100

2,2^x+2-2^x=96

2^x(4-1)=96

2^x=96:3=32

-> x=5

tổng số tuổi của 24 bạn là:

24x11=264 tuổi

tổng số tuổi của cô giáo và các bạn là:

12x25=300 tuổi

tuổi cô giáo là 300-264=36 tuổi

1 what does your father do?

2 when does hoa's class start?

3when do they have Civic Education?

4 where are the magazines?

5 what is her favorite subject

6 what can we buy at breaks

7 why is hong unhappy

8 Who is Hoa talking to

9 Where do we live?

The students/ offer/ Bowers/ the vistors

chia V

It suddenly..(begin)  to rain while Lẩu   (sat) in the garden 

2. I (walk) along the street when I suddenly  (feel) something hit me in the bback. I .../.(not know) what it was

sắp xếp từ: 1. enough/ Jane/ stay / to/alone/ old/isn't/at home

that/ delicious/beef stew/ smells

2. about/ Mark/ something/ upset/ looks

3. they/ gave me/ round/ photograp frame/ a/ silver-plated/ gorgeous

4. carpet/ a(n)/ Mia/ bought/ old/beautiful/ Chinese

5.wore/silk/and/Julie/a/pink/brown/dress

6. the neighbors's/ kept/ me/party/awake/all night